public function getIsExpired()
    {
        $createdAt = $this->getCreatedAt();
        if ($this->getExpiredAfter() === false || $createdAt === null) {
            return false;
        }
        if ($this->timeType == static::$timeTypeLocal) {
            return $this->getDatetimeOffset($this->offsetDatetime($this->currentDatetime(), -$this->getExpiredAfter()), $createdAt) > 0;
        } elseif ($this->timeType == static::$timeTypeUtc) {
            return $this->getDatetimeOffset($this->offsetDatetime($this->currentUtcDatetime(), -$this->getExpiredAfter()), $createdAt) > 0;
        }
        return false;
    }