The fact that the spare key starts the car for a couple seconds then it stops suggests that the RFID chip is not matched to the car. I'm not sure why the original key will not turn, but the second key does. Nonetheless, it sounds like if you can get the RFID chip from the original key into the second key that turns you would have one fully functioning key.
Go to the post on key disassembly.

https://www.crossfireforum.org/forum...estroying.html

You want to take the "transponder" (RFID chip) from the original key and replace the one in the second key with working fob with it. Two RFIDs in close proximity would not likely work.
Hope this fixes your problem and gets you one fully functioning key.