Maybe change "date and time" to "date" in Expiration Date
If experation dates are always only per day and not hours:minuttes:seconds then maybe this strings should be changed:
https://gitlab.gnome.org/GNOME/seahorse/-/blob/master/help/C/pgp-create.page#L105
Currently the string make it sound like you can set hours:minuttes:seconds.
select an expiration date and time for it
Maybe change to:
select an expiration date for it
But i am not sure that you can only set by day.