Are you on vacation or is this a business trip? I was also in Athens a few months ago, and I was picked up at night by a driver I found on https://gettransfer.com/en , and the fare was only 50 euros. I thought that all taxis charge double the price at night, but I think I was very lucky. Athens has a fairly large airport, and it was my first time there, I was looking for a car for a long time because I was still not well oriented, and the driver was very patient. Shall I recommend you my favorite places in Athens?