Interact with API's using same OAuth ClientId in different environments

I have created a OAuth App in order to Interact with API’s. I use same OAuth App (Same client ID) for testing environment and production environment.

Question is If I’m to login (one account) in to test and production sequentially at a given time (before the token expire) and get two different access_tokens .

Both access_tokens are valid or is it the latest access in this case production access_token?