How should I decline a social work event?

There’s a lunch and social event that my job is having that’s coming up. It’s during the work day, so we’re going to have lunch and then bowling after. I was planning on staying for the lunch because, free food lol, but I would rather go home and have the rest of the day to myself. Not to mention it’s on a Friday so I would get to start off my weekend early. I appreciate my job for providing all of these nice things for us, but when it comes to social events at work, I’m just not interested in attending and socializing with coworkers as they’re not really my cup of tea even though they are nice people. Id rather spend time with my friends and loved ones. I just don’t know how to decline, since I’m sure they will ask why I won’t be attending since it’s encouraged that team members go to these events. I also can’t use the excuse of “I have prior commitments” since it’s during the work day. Any advice?