Android : validate instagram token on app's startup

i am using this guide to authenticate instagram users, the problem i have is that when the app launches, i don't know if the token i have is still valid anymore (user could revoke it etc...) i need to test the validity of the token on the applications's start-up,

i couldn't find a solution one on the web so i just tried making a request and see if i get a response or an error with the following call

"https://api.instagram.com/v1/users/self?access_token=" + mySavedToken

this method works, but is incredibly slow, how can i validate my token in a faster way?