Guest access by oauth2

Good day everybody!
I try to integrate AWS Appsync (Graphql server) and Okta by oidc. All are working from box, but AppSync doesn’t support guest access (it requires jwt for all requests).

After research I have found one solution/idea - to create a user for guest operations. But how can I get manually jwt from back end (lambda)?
Or if it is impossible Can I use another ways to solve this problem?

Thank you!

I found the good way for getting token - to use rest endpoint - token (v1/token).