I am going tell you a little secret in my 25 years in the car business, 2 car keys are always better than one car key. In all the years I have bought cars at auction or taken them in trade, cars that come in trade with both keys (2) are usually better.
Why? 9 times out of 10 we spend less to recondition a car that has both keys then a car with one key. Why? If previous owner lost a key, they took the time to find it or, had a second made. When it came time to trade that car in they made sure they gave 2 keys. Typically cars with 2 keys had better maintenance history, cleaner carfaxes, cleaner cars, because the previous owner was more engaged in ownership. They cared about their car to get a second key, to find the key, and probably to get that car into the shop when they heard or felt something that was not correct.
Some may argue with me or give an example of the car they bought with only one key, but from my professional experience, cars with 2 keys are better than 1. At auction, I always look for the cars with 2 keys, not one!