Yes, that looks like a wallet.aes.json file from blockchain.info.

This thread have the info of old and new private key types: [overview] Recover Bitcoin from any old storage format]
But there's nothing about a 33-character prv key.

Have you tried to drag-n-drop it to their import wallet page (https://login.blockchain.com/wallet/import-wallet)?
Said, it supports blockchain.info wallet files.