School age? Buy raisins en vrac in the bioshop and put them in a little box.
Here traditionally there would be no snack. Breakfast, lunch at 12, goûter at 4 or 4.30 but you need more than raisins, supper at 7.30 or 8.
(I gave mine those sunmaid boxes of raisins too, in the UK, when they were pushchair size.) They don’t really need to be grazing all the time though and school may well not approve.