In theory beans might be all right.
[I like to gently delude myself sometimes to stay sane.]
According to a tin of Heinz beans which I just {cough} happen to have to hand there are 12.5g of carbs per 100g which is not TOO bad. Half a tin is 26g of carbs, which with a Lidl roll comes to 35g of carbs. Too high for a 20g a day low carber, but if you are shooting for below 50g then it looks all right.
So one treat is a Lidl roll split in 2, and grilled with cheese on. Cheese on toast with Heinz beans. Drool!
Another treat is a cheese omelette with half a tin of beans.
I could probably get the same pleasure if I split the tin 3 or 4 ways. Well, nearly as much. Perhaps 3 ways?
Safe(ish) treats when you are feeling down are something worthwhile to plan into your lifestyle.