Any way to transfer golden keys?

Solution 1:

Golden keys are tied to your SHiFT account, and cannot be bought, sold, traded, or otherwise used for any purpose but opening the golden chest in Sanctuary.

According to an official source on the Gearbox forums:

Keep in mind that you cannot trade or sell Golden Keys, and once you’ve used a Key to open the Golden Chest, that Key is gone for good.

However, the loot you get from the chest is just normal loot and can be traded normally.

If you need more on a character, you might consider keeping track of a list of SHiFT codes - there are codes for multiple keys that pop up from time to time.