protected function getValue($key)
    {
        if (!array_key_exists($key, $this->store)) {
            throw new KeyNotFoundException();
        }

        $getResult = $this->store[$key];
        $unserialized = @unserialize($getResult);

        if (Util::hasInternalExpireTime($unserialized)) {
            $this->handleTtl($key, $unserialized['ts'], $unserialized['s']);

            $getResult = $unserialized['v'];
        }

        return $getResult;
    }