Hi there. Yes it will work in Spain, it is only locked for China.

There is no code, as an Activision/Blizzard official partner we use direct activation. You can read more about it here: https://us.gamesplanet.com/support/23-activations/271-activation-with-battle-net-direct

The game is directly activated on your battle.net account, same way as you would buy it through battle.net :)