If there is a question or need to validate the expiry values, without having access to the token, it can be done through the FWSTrace log.
In the FWSTrace.log, the access, refresh, and identity token values are logged.
Below are examples of the expiry set for the default 5 mins as well as 30 minutes. Search for "expires_in".
Ex. 5 mins
[access_token=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX, refresh_token=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX, id_token=XXXXXXXXXXXXXXXXX, expires_in=300, token_type=Bearer]]
Ex. 30 mins
{"access_token":"XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX","refresh_token":"XXXXXXXXXXXXXXXXXXXXXXXXXXX,"id_token":"XXXXXXXXXXXXXXXXXXXX,"expires_in":1800,"token_type":"Bearer"}]]