snack bar; light-meal restaurant
A casual eatery serving light meals, snacks, or simple dishes, often with a counter or small seating area.
A new snack bar opened in front of the station.
I ordered a sandwich and coffee at the light-meal restaurant.
食堂 is a general dining hall or cafeteria, typically offering full meals, whereas 軽食店 specializes in lighter fare.
Compound of 軽食 (light meal) + 店 (shop, store).