If I'm reading the code correctly, this uses the duration of your "time lock" as the duration for how long it will perform scrypt operations on the key derivation.

In other words, if you say you want to "lock" the secret for 5 days, the code will perform scrypt to generate the key for 5 days!!! Then it expects you to remember the iteration count to decrypt it.

I don't see any use case where that's a useful mechanism. Especially since it ignores other computers are likely faster at scrypt then yours is.