You will get reward if you win the battle. Reward amount will be calculated in this way:
Reward = Base Reward + Base Reward * Speed / 1500
You can see Base Reward amount from the table in Enemies section.
Your reward will be locked for 48 hours and after the lock period, you can claim your reward at any time. Claim fee is 30% and it reduces by 2% everyday from the last claim.
Reward = Reward * (100 - (30 - 2 * Days passed from last claim)) / 100