expStr := claims["exp"]
	if expStr == "" {
		return ErrTokenExpired
	}

	// No custom duration requested, the claims can be used as is.
	if dsecs == "" {
		return nil
	}

	if _, err := auth.ExpToInt64(expStr); err != nil {
		return err
	}

	defaultExpiryDuration, err := GetDefaultExpiration(dsecs)
	if err != nil {
		return err
	}