To check the mode of the store, you can go to the site or enter the phrase in Google
Holiday name kauppojen aukioloajat name of shop
For example, to find out the schedule for Prisma's opening hours on Easter, enter
Pääsiäinen prisma aukioloajat
Then you need to select the store in which you are traveling and on its page see the schedule.
If you are interested in a particular holiday - go on its page by clicking on the name in the table.