I assume you are using the key because the fob no longer works. Put a new battery in it and see if it works. If not you will need to have the key and fob reset to work with the vehicle. The vehicle should not sound the alarm when you use the key. I assume the key still starts the engine but something is wrong that it doesn't recognize the key in the door. Take care of it soon or it may not start the engine just when you really need to go somewhere.
Answers & Comments
I assume you are using the key because the fob no longer works. Put a new battery in it and see if it works. If not you will need to have the key and fob reset to work with the vehicle. The vehicle should not sound the alarm when you use the key. I assume the key still starts the engine but something is wrong that it doesn't recognize the key in the door. Take care of it soon or it may not start the engine just when you really need to go somewhere.