Creating a token with no expiry - for testing

I am looking to create an access_token to use for tests against an API that is using access_tokens for authenticating requests. The API is using the RS256 algorithm. From what I can tell Auth0 holds the private key for generating these.

Is it possible to create an access_token that has no expclaim in the payload, without using the private key? Or, any other ideas on how to do this?

The recommended way to increase the token expiration is to set it from the API dashboard:
Dashboard > APIs > Your API > Token Expiration (Seconds)

You can then cache the token to reuse during testing.