To check how many hero tokens you currently have, go first to your list of survivors. Tap the TWD symbol, and it will open up a list of your Heroes.
For the heroes that are still locked, you can see here how many you have collected and how many you still need to unlock them.
For the heroes that are still locked, you can see here how many you have collected and how many you still need to unlock them.
For the heroes you have unlocked, tap the hero and you can see the amount of tokens you have on the left side of the screen.