code: public static boolean isConfirmationKeyValid(final String confirmationKey, final Integer validityPeriod) {
  
  		final String[] parts = confirmationKey.split("!");
  
  		if (parts.length == 2) {
  
  			final long confirmationKeyCreated = Long.parseLong(parts[1]);
  			final long maxValidity            = confirmationKeyCreated + validityPeriod * 60 * 1000;
  
  			return (maxValidity >= new Date().getTime());
  		}
  
  		return Settings.ConfirmationKeyValidWithoutTimestamp.getValue();
  	}
docs: Determines if the key is valid or not. If the key has no timestamp the configuration setting for keys without timestamp is used
  
  @param confirmationKey The confirmation key to check
  @param validityPeriod The validity period for the key (in minutes)
  @return