After you file

@KonfusedKent 

If an option that was granted (written) expired, enter the expiration date in column (b) and enter “Expired” in column (e).

From this you can see that a short is always a short term capital gain or loss, no matter how long you are short.

your proceeds is the premium you received.

the cost basis is zero. (IRS says enter EXPIRED, but TurboTax won't do that for you.)

you don't report this as worthless securities.