How to auth requests to Ory Keto (by API Token for example)

[Disimasa]

I'm trying to use Ory Keto for my project. I already created keto service and it works fine. However, before I deploy it, I want to add some security for requests. I know that I can use Ory OathKeeper, but I want some simpler solution as API Token check. In @ory/keto-client for js there's the apiKey argument in BaseAPI configuration (so I guess API Token check is possible). However I couldn't find any information how to create this check on Ory Keto side. How can I implement such check? Or maybe there're some better solutions?