The OAuth Access Token's 1 hour expiration cannot be extended. It can however, be refreshed so you can keep an active OAuth Access Token.
How to Refresh an OAuth Access Token:
Once you have an active OAuth Access Token and Refresh Token, make a POST request to
https://zoom.us/oauth/token with the following query params and authorization header:
|refresh_token||Your refresh token.|
|Authorization||The string "Basic" with your Client ID and Client Secret with a colon : in between, Base64 Encoded. For example,
Refresh tokens expire after 15 years, however, the latest refresh token must always be used for the next refresh request. If you use an prior refresh token to make a Refresh Request, you will receive an "Invalid Token!" error message.