Locked implies it could eventually be unlocked. Sounds less final.
Can't really lock and then unlock an npub because the nsec can't change, as far as I know.
Discussion
A lot of events are signed with the key, and very hard to delete all, to keep but locked will allow history/backup, before retire.
Are you defining
"locked" as "frozen, but don't delete anything, yet"
versus
"retired" as "already locked and events now ready for deletion"?
Or are you using locked as a different word for the second thing?