Tại sao website viết bằng laravel có thời gian TTFB khá cao trên 2 giây

Mình lấy dữ liệu qua ajax phương thức GET. Kiểm tra trên F12 của chrome thì thời gian TTFB khá cao: 2.5 s.-> Như vậy xác định nguyên nhân do server. Tuy nhiên khi kiểm tra debuger thì thời gian query dữ liệu trên server chỉ 4.65ms. Vậy cả nhà giải đáp giúp mình TTFB cao do đâu ạ. Bình thường TTFB chỉ 80-90ms chứ nhỉ? Dưới đây là code của mình. Ajax

$(document).ready(function() {
    $(".btn-search-order").click(function() {
        $.ajaxSetup({
            headers: {
                'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
            }
        });
        $.ajax({
            type: 'GET',
            url: '/search/month=' + $("#search_month option:selected").val()+'/status='+ $("#search_status option:selected").val() +'/item_name='+ $("#myInput").val(),
            dataType: 'json',
            success: function(data) {
                console.log(data);
            }
        });
    });
});

Route

<?php

use Illuminate\Support\Facades\Route;
Route::get('/history', [
	'as' => 'Nhat-Ky-su-dung',
	'uses' => 'PageController@getHistory',
	'middleware' => 'auth']);
Route::get('/report',[
	'uses' => 'PageController@GetReport',
	'middleware' => 'auth'])->name('GetReport');
Route::get('/user', [
	'as' => 'Khach-hang',
	'uses' => 'PageController@getUser',
	'middleware' => 'auth']);
Route::get('/role',[
   'middleware' => 'role:superadmin',
   'uses' => 'MainController@checkRole',
]);
Route::get('/', [ 'uses' => 'OrdersController@index', 'as' => 'orders.index','middleware' => 'auth']); 
Route::get('/order', [ 'uses' => 'OrdersController@index', 'as' => 'orders.index','middleware' => 'auth']); 
Route::group(['prefix' => 'order', ], function () { 
    Route::get('/{id}', [ 'uses' => 'OrdersController@show', 'as' => 'orders.show',]); 
    Route::post('', [ 'uses' => 'OrdersController@store', 'as' => 'orders.store',]); 
    Route::put('/{id}', [ 'uses' => 'OrdersController@update', 'as' => 'orders.update',]); 
    Route::delete('/{id}', [ 'uses' => 'OrdersController@destroy', 'as' => 'orders.destroy',]);  
});
Route::get('/search/month={month}/status={status}/item_name={item_name}',[ 'uses' => 'OrdersController@search_order', 'as' => 'orders.search_order',]);
Route::get('/payments', [ 'uses' => 'PaymentsController@index', 'as' => 'payments.index','middleware' => 'auth']); 
Route::group(['prefix' => 'payments', ], function () { 
    Route::get('/{id}', [ 'uses' => 'PaymentsController@show', 'as' => 'payments.show',]); 
    Route::post('', [ 'uses' => 'PaymentsController@store', 'as' => 'payments.store',]); 
    Route::put('/{id}', [ 'uses' => 'PaymentsController@update', 'as' => 'payments.update',]); 
    Route::delete('/{id}', [ 'uses' => 'PaymentsController@destroy', 'as' => 'payments.destroy',]); 
});
Route::get('/exchange-rates', [ 'uses' => 'ExchangeRatesController@index', 'as' => 'ExchangeRates.index','middleware' => 'auth']); 
Route::group(['prefix' => 'exchange-rates', ], function () { 
    Route::get('/{id}', [ 'uses' => 'ExchangeRatesController@show', 'as' => 'ExchangeRates.show',]); 
    Route::post('', [ 'uses' => 'ExchangeRatesController@store', 'as' => 'ExchangeRates.store',]); 
    Route::put('/{id}', [ 'uses' => 'ExchangeRatesController@update', 'as' => 'ExchangeRates.update',]); 
    Route::delete('/{id}', [ 'uses' => 'ExchangeRatesController@destroy', 'as' => 'ExchangeRates.destroy',]); 
});
Auth::routes();

Controller

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;
use App\Orders;
use App\User;
use App\order_historys;
use Illuminate\Support\Facades\Validator;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Auth;

class OrdersController extends Controller
{
    public function index(Request $request)
    {
        if(Auth::user()->type==1){
            $orders = DB::table('Orders')
                ->join('Users','Orders.user_id','=','Users.id')
                ->select('Orders.*','Users.name')
                ->orderby('created_at','desc')
                ->get();
            return view('Admin.Orders.Order_index')->with('orders',$orders);
        }
        else{
            $orders = DB::table('Orders')
            ->join('Users','Orders.user_id','=','Users.id')
            ->select('Orders.*','Users.name')
            ->where('user_id', '=', Auth::user()->id)
            ->orderby('created_at','desc')
            ->get();
            return view('Admin.Orders.Order_index_user')->with('orders',$orders);
        }
    }

    public function store(Request $request)
    {
        $validator = Validator::make($request->input(), array(
            'item_name' => 'required',
        ));

        if ($validator->fails()) {
            return response()->json([
                'error'    => true,
                'messages' => $validator->errors(),
            ], 422);
        }
        $orders = new orders();
        if(Auth::user()->type!=1){
            $orders->user_id = Auth::user()->id;
        }
        else{
            $orders->user_id = 1;
        }
        $orders->status = 0;
        $orders->item_name = $request->get('item_name');
        $orders->quantity = $request->get('quantity');
        $orders->price = $request->get('price');
        $orders->link_order = $request->get('link_order');
        $orders->memo = $request->get('memo');
        $orders->total_amount = $request->get('price')*$request->get('quantity');
        $orders->amount_oc = $request->get('price')*$request->get('quantity')*3450;
        $orders->save();

        // $order_historys = new order_historys();
        // $order_historys->order_id = 

        return response()->json([
            'error' => false,
            'orders'  => $orders,
        ], 200);
    }

    public function show($id)
    {
        // $orders = Orders::find($id);
        // $orders = DB::table('orders')
        // ->where('id','=',$id)
        // ->get();
        return response()->json([
            'error' => false,
            'orders'  => $orders,
        ], 200);
    }

    public function update(Request $request, $id)
    {
        $validator = Validator::make($request->input(), array(
            'item_name' => 'required',
        ));
        $status = orders::find($id)->status;
        if ($validator->fails()) {
            return response()->json([
                'error'    => true,
                'messages' => $validator->errors(),
            ], 422);
        }
        $orders = orders::find($id);
        $orders->status = $request->get('status');
        $orders->bill = $request->get('bill');
        $orders->item_name = $request->get('item_name');
        $orders->link_order = $request->get('link_order');
        $orders->kg = $request->get('kg');
        $orders->quantity = $request->get('quantity');
        $orders->price = $request->get('price');
        $orders->total_amount = $orders->quantity*$orders->price;
        $orders->amount_oc = $orders->quantity*$orders->price*3450;
        $orders->memo = $request->get('memo');
        $orders->save();
        return response()->json([
            'error' => false,
            'orders'  => $orders,   
        ], 200);
    }

    public function destroy($id)
    {
        $orders = Orders::destroy($id);

        return response()->json([
            'error' => false,
            'orders'  => $orders,
        ], 200);
    }
    public function search_order($month, $status, $item_name)
    {
        $orders = DB::table('Orders')
        ->whereMonth('created_at', '=', $month)
        ->where('status','=',$status)
        ->orderby('created_at','desc')
        ->get();
        return response()->json([
            'error' => false,
            'orders'  => '$orders',
        ], 200);
    }   
}