public static function csrfExpirated($time = null)
    {
        if (Session::getInstance()->has('__bow.csrf')) {
            return false;
        }

        if ($time === null) {
            $time = time();
        }

        $csrf = Session::getInstance()->get('__bow.csrf');

        if ($csrf['expirate'] >= (int) $time) {
            return true;
        }

        return false;
    }