v2board/app/Http/Controllers/Guest/TelegramController.php

<?php

namespace App\Http\Controllers\Guest;

use Illuminate\Http\Request;
use App\Http\Controllers\Controller;

class TelegramController extends Controller
{
    public function __construct(Request $request)
    {
        if ($request->input('access_token') !== md5(config('v2board.telegram_bot_token'))) {
            abort(500, 'authentication failed');
        }
    }

    public function webhook(Request $request)
    {
        info($request->input());
    }
}