Zero Knowledge proof of encryption

Is it possible to create a zero knowledge proof that a secret has been encrypted and not some "garbage"?

Example: We want to reveal a secret key for a given public key after time T. We use timelock to encrypt the secret. Is it possible to prove to someone (without revealing the secret) that the secret key was encrypted with timelock for the corresponding public key?

No file, test, or entry point is named. Start by reviewing the tlock-js TypeScript timelock-encryption implementation and determine whether it exposes enough structure to prove encryption for the corresponding public key without revealing the secret; done would require a concrete, agreed approach.

Written by the indexing model from the issue text.