Unlock my locked phone/use phone while on lockdown

Ok so during school my phone is on downtime, but at lunch break we have 1 hour we are allowed to use our phones, is there any way I can play Spotify on my earbuds while it's locked, or unlock it w/out the password/without my parents knowing? Rn it completely shuts off my phone and alerts my mum if I enter the password for a setting through my phone. If there's absolutely no way I'm thinking about getting a cheap phone to use just for school.