How can I see the creation and expiration timestamp of my keys?
With --list-key I only see the date without time.
If you want the time in addition to the date, I guess that only of the debugging options may help, but I am not sure.
You can use:
gpg -a --export <email-adress_or_id> | gpg --list-packets
to get the creation time as seconds since unix epoch (look for “created” in the output)
(https://stackoverflow.com/questions/48914338/how-to-get-expiration-date-from-a-gpg-key/48915209#48915209)
There is also a line with “key expires after” which shows the the whole duration from creation to expiration. You would have to calculate the exact expiration time but that should be no problem 
Two other solutions were mentioned in the mailinglist:
the option --with-colons
--full-timestrings (since 2.3.0)
https://lists.gnupg.org/pipermail/gnupg-users/2023-January/066380.html