public function isConfirmationExpired()
    {
        $ttl = \Config::get('df.confirm_code_ttl', 1440);
        $lastModTime = strtotime($this->last_modified_date);
        $code = $this->confirm_code;

        if ('y' !== $code && !is_null($code) && ((time() - $lastModTime) > ($ttl * 60))) {
            return true;
        } else {
            return false;
        }
    }