What to run
Open JWT Decoder, Unix Timestamp Converter, and Epoch Now. All three stay in the browser.
How to read the result
exp is seconds since the epoch, UTC. Convert it.
If Epoch Now is greater than exp, the token is expired by its own claim.
That still does not mean the signature was valid.
What to open next
Stop before claiming the token was accepted by the server. PageUtil cannot verify it.