It is very simple! After logging in to your GoGet account, click on Lazada Orders and you will be able to see the expiration date on the top left corner as shown in the picture below.
Periodically, its good practice to check when the token is expiring. All tokens have a validity of 180 days and once refreshed, it will extend the token by another 180 days. Click here to learn how to refresh the token and the importance of doing so.