You could build something where the human never had the actual key. The human has a passphrase which goes to a piece of hardware with the actual key, either tamper-responding physical hardware with a clock, or some kind of network service (e.g. a .onion service) which takes the user's passphrase and returns a key. As long as the user (or subverted hardware) doesn't retain the actual key each time, it's probably ok, and protected from this particular case of compelled disclosure.

The ideal is to use some kind of tamper-responding hardware to process the data (as well as decryption), though. And probably locally -- I don't think I'd trust an .onion service to stay up if it disappearing meant I would no longer have access to my files.

I reckon you could make hardware tamper-proof by setting the hardware in a booby-trapped container that would self-destruct if tampered with. Make sure that the only two connections coming out of the booby-trapped container are power and a data connection over which the memory of the device cannot be accessed, such as ethernet.