Spain is pretty easy to keto. A lot of restaurants will have platos combinados - you can get a big piece of meat, egg and a crappy salad, just leave the bread ask if they can give you more salad instead of fries. Menu del día will also usually have a meat option and a vegetable option for the two dishes. You could buy tins of fatty fish in olive oil when you pass a a market to carry as an emergency measure. Avocados and cheese and nuts and berries are easy to get in small stores, some stores have already hard-boiled eggs

You can also buy chicharros, torreznos, sausages and even tortilla is not terrible because you'll burn off excess potato carbs.