That’s what nip94 allows for and that’s what gets published once it’s uploaded to nostr:npub1nxy4qpqnld6kmpphjykvx2lqwvxmuxluddwjamm4nc29ds3elyzsm5avr7 

If you read the specification, a nip94 event has the sha256 hash, a url and a fallback url

The url is convenient right now because no clients that I’m aware of query sha256 hashes like you are mentioning; however, this process sets up that foundation to be possible in the future for clients to query hashes like you’re proposing