To make use of the standard aio endpoint authentication you would likely need to implement the full oauth token generation process in your codebase, taking your client key etc and using the token API to convert this into a token. You could potentially cache this for a period of time to avoid every call to the service needing to generate a new token.
An alternative approach would be to look at disabling the "adobe auth" option in the adobe io worker, then implement your own authentication, eg pre-shared key etc. This potentially simplifies the flow, but you need to consider the security impact of doing this as the adobe io API endpoint is effectively public.
You can disable the out of the box auth requirement for the endpoint by updating the manifest.yml
annotations:
require-adobe-auth: true
