Yes, but only in moderation, not more than a few times a week.
Also it is very important you remove all the green parts (stem, leaves, etc) of the tomatoes first before giving it to them. The leafy parts contain solanine which is poisonous to guinea pigs.
If you are unsure of which parts of a cherry tomato a guinea pig can have it is best to avoid this food all together. It is not worth risking your pets life over this food.