Boss won't let me leave early for school pickup

There's a 'no early departures' policy at my company even though I work my 8 hours. School pickup is at 3pm. I've asked to start at 7am and leave at 3pm. Seems reasonable but my boss says everyone needs to be here till 5. Looking for new job honestly. Not working 60 hours a week to miss my kids growing up. Any of you dealt with this?