Check your surroundings carefully. It's possible that you simply misplaced your keys and they're somewhere nearby. Retrace your steps and check all the places you've been recently.
If you can't find your keys, call a locksmith or roadside assistance. A locksmith will be able to open your car door and make you a new key on the spot. Roadside assistance may also be able to help, but they may need to tow your car to a dealership to get a new key made.
If you have a spare key, use that to get into your car. Once you're in your car, drive to a safe location and call your dealership to order a replacement key.
If you don't have a spare key, you will need to order a new key from your dealership. This process can take a few days, so you may need to arrange for transportation in the meantime.
Tips for preventing lost car keys:
Create a habit of putting your keys in a specific place when you get home, such as on a hook by the door or in a bowl on the kitchen counter.
Consider getting a spare key made and keeping it in a safe place, such as your wallet or purse.
Consider getting a smart key fob that can track your keys and help you find them if they're lost.
Please note that the cost of replacing lost car keys can vary depending on the make and model of your car and the type of key you need. Traditional keys are typically the least expensive to replace, while smart key fobs can be the most expensive.