Look on the box in which your key came. If you still have the box, or the information on the white label from the box, contact the Wilson Bohannan Co., and the company will send you a new key. Most hardware stores would not have the key blanks required to cut you a new key.
Call a locksmith. If you don't have the keying information from the box, and the lock is valuable or an antique, a locksmith can disassemble the padlock, identify the pins and rebuild the lock, according to a WB spokesman. This method costs more than most padlocks.
Destroy the padlock if you cannot find the box or do not wish to pay for a locksmith. You must cut through the bar, as using a hammer or some other means of forcing it would probably not work. Use a hacksaw with a metal-cutting blade.