How to point identity source of authorizer lambda to a cookie?

Question

I have authorizer lambda that I want its identity source to be a cookie, how can I achieve this?

I want to point it to a specific cookie because I don't want to pass the authorization token in a header because that means I'll have to allow my client to have programmatic access to the token which is not secure at all, and I prefer to use secure httpOnly cookies for such tokens.