在laravel中验证APIKEY Mailchimp

I am trying to validate apikey , my scenario here is when am as a user enter apikey like xxxxxxxxxxxxxxxx-us17 i am saving this apikey in database as a user_id what i want here when i enter this key this key should check from mailchimp if its valid apikey that a user is enter if its a valid then good to go. if its not there should be a message not valid api key. On my side its allowing to enter any randon apikey which is not allowed in any case.

I am trying to solve this problem from a couple of days: Here is my full controller:

namespace App\Http\Controllers;

use App\APIKEY;
use DrewM\MailChimp\MailChimp;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Validator;
use Mailchimp\MailchimpFacade;



class ApiController extends Controller
 {

 public function authenticateApiKey(Request $request)
{
    $fieldsValidation = [

        'api_key' => 'required|unique:apikey,api_key',

    ];
    $validator = Validator::make($request->all(), $fieldsValidation);

    if ($validator->fails()) {
        $resultArray = [
            'status' => 0,
            'message' => $validator->errors()->first(),
            'dataArray' => []
        ];

    } else {

        $api = new APIKEY($request->all());
        $mailchimp_ping = new MailChimp($api);
        print_r($mailchimp_ping);die;
        $mailchimp_ping = $mailchimp_ping->get('/helper/ping');
        if (!$mailchimp_ping) {

            $errorResponse = [
                'message' => 'Not valid api key!',
                'error' => '401'
            ];
            return \Illuminate\Support\Facades\Response::json($errorResponse);
        }

        else

            {

            $request->user()->apikey()->save($api);
            $resultArray = ['status' => 1, 'message' => 'Mailchimp Api key added into system successfully!', 'dataArray' => $api];
            return \Illuminate\Support\Facades\Response::json($resultArray, 200);
        }
    }
}

THe main code where i am trying to validate apikey from maiilchimp is:

        $api = new APIKEY($request->all());
        $mailchimp_ping = new MailChimp($api);
        print_r($mailchimp_ping);die;
        $mailchimp_ping = $mailchimp_ping->get('ping');
        if (!$mailchimp_ping) {

            $errorResponse = [
                'message' => 'Not valid api key!',
                'error' => '401'
            ];
            return \Illuminate\Support\Facades\Response::json($errorResponse);

Your help will be highly appreciated !