Generating long-lived tokens for CI/CD with Genesys Cloud

Quick question about generating long-lived tokens for CI/CD pipelines. We need a token that survives past the standard 90-minute window for overnight data action runs. I tried using /api/v2/authorization/tokeninfo but it returns 401 Unauthorized when I pass the initial grant. Is there a specific grant_type or scope I’m missing in the POST body to get a persistent credential, or do I have to script a refresh loop?