https://dev.twitch.tv/docs/authentication#revoking-access-tokens explains how to revoke an OAuth token. Logging into the account the OAuth token belongs to, and disconnecting the app that generated the token from your connections page https://www.twitch.tv/settings/connections should also revoke the token.
If by regenerated your key, you mean your secret key for your app, that doesn’t invalidated tokens that have already been created with it.