Bought a Apple se watch at pawn shop and it is locked how do I get it unlocked

The only way you will be able to use that watch is if the original owner enters the activation code. This is a security feature that stops people from using a stolen watch. If you cannot get in touch with the original owner, then try to get a refund from the pawn shop. You will not be able to use that watch.

Here is some advice if you are considering the purchase of another watch from an unauthorized seller:

Before you buy an Apple Watch from someone other than Apple or an authorized Apple reseller, make sure that the device is no longer linked to the previous owner’s account.

1. Identify the model of Apple Watch. 
2. Make sure that the previous owner removed Activation Lock from the watch and that the watch has been erased. They must unpair the watch and remove Activation Lock by entering their Apple ID password, so you can use the watch. 

• • If you see the passcode lock screen or the Home screen, the device needs to be erased. 
  • If you can, try to pair the watch with your iPhone. If you're asked to enter the previous owner's Apple ID password during setup, then Activation Lock is still on.

1. For cellular models of Apple Watch, make sure that the previous owner removed and cancelled any active cellular plans.