How to extend the Appzillon OTP expiry time?

How to extend the Appzillon OTP expiry time? Is there any predefined option to change the time? If yes, please let me know else provide the sample code fix to achieve the same. An earlier response will be much appreciated.
For Using OTP generation (setting otp length, otp expiry time ) you need to follow below steps.
1. Create a custom interface in the app.
2. Give implementation class name in the interface under "user impl class". (Ex : com.iexceed.otpservice.GenrateOtpImpl)
3. Save the interface, now go to your custom class and extends "com.iexceed.appzillon.iface.ExternalServicesRouter".
Ex :
public class GenrateOtpImpl extends ExternalServicesRouter{

public void serviceRequestDispatcher(Message pMessage,
SpringCamelContext pContext) throws ExternalServicesRouterException,
InvalidPayloadException, ClassNotFoundException, URIException, JSONException {
//write your logic here
Request lRequest = pMessage.getRequestObject();
JSONObject lgenOTPJSON = new JSONObject();
lgenOTPJSON.put("payload", lRequest.getRequestJson());
lgenOTPJSON.put("otpExpirySecs", "300"); // you can set OTP expiry time in seconds according your requirement
lgenOTPJSON.put("otpLength", "6"); // you can set otp length according your requirement
//set request format
pMessage.getRequestObject().setRequestJson(new JSONObject().put("generateOTPRequest", lgenOTPJSON));
com.iexceed.appzillon.services.otp.OTPEngineService otpEngine = new com.iexceed.appzillon.services.otp.OTPEngineService();
otpEngine.generateOtp(pMessage); // for generating OTP
response = pMessage.getResponseObject().getResponseJson(); // OTP response received
LOG.debug("OTP Response is " + pMessage.getResponseObject().getResponseJson());
String otp = pMessage.getResponseObject().getResponseJson().getJSONObject("generateOTPResponse").get("otp") + ""; // OTP received
}
}