Here is an example of a recently programmed car key. This example is a smart (proximity) key for a 2018 Mitsubishi. Because these keys don’t have to be put into the ignition to start the car, they do seem to get lost more easily.
Always remember that proximity keys can render your car vulnerable to theft. A criminal doesn’t need to have your key physically in his hand to start your vehicle. Always leave the keys at the opposite end of the house to the car. Or put them in a suitable RF blocking sleeve or metal box.