Kia Troubleshooting Questions? Ask a Mechanic
What you are describing sounds like a bad chip in the key or a bad receiver in the dash that accepts the signal from the key. Do you plan to do any repairs on it yourself?
Your best bet is to have an automotive locksmith or a shop with a good scan tool check for communication between the key and the transceiver in the dash. If the communication is weak they will be able to tell if the problem is the key or the transceiver. They can then replace the problem part. It is most likely that the key is dying. The transceiver in the dash rarely acts up on these cars.
Please let me know if you need additional information.