Check if an extension is in use before dropping it in a postgres db

Question

I want to drop unnecessary extensions in my database. But before i do that , i want to make sure that they are not being used anywhere in the database. I have tried using the below query to find functions that make use of the extension like pgcrypto . Im not sure if this is enough

select proname,prosrc from pg_proc where prosrc ilike '% encrypt%'