If {
CSFS(nostr key, event ID)
} else {
CLTV 5 years in future
}
They either put true and have to provide a valid sig for the event or put false and it'll verify the tx's lock time that it is at the expected date
Discussion
Would have to hand craft the nostr note to make sure an exact time was included. 🤔
This seems scary for some reason, as it relies on serialization of data outside bitcoin. Would really need to be sure nostr serialization wasn't going to change within that time frame.
You don't have to put the whole note in the script just the event Id that you sign. If nostr changed, then you could still just sign the hash, but the note won't be valid.