That looks like the right config value. Some things to check:
1. Are there duplicate `oauthConfig` stanzas (or tokenConfig, etc) in your config file? I think the last one wins.
As an aside, for external integrations with machine accounts, service account tokens are recommended (https://docs.openshift.org/latest/dev_guide/service_accounts.html)... they don't expire, but can be revoked.