Verify JWT token signature of custom created tokens

Question

I am new to PHP (Laravel), i am using tymon JWT library. I generated a custom token, now i want a way to verify its signature knowing that the token is not going to be extracted from header or request object it is like a stand alone token ex:eyJ0eXAiOiJK.eyJzddSwsd.C1PCr4D

I am using JWT tokens for other purposes than authentication, so this method of validating credentials wouldn't help or middlewares

    if (! $token = JWTAuth::attempt($credentials)) {
        return Response::json(['error' => 'invalid_credentials'], 401);
    }