If you use frozen shrimps, let them defrost overnight in the fridge. Drain the shrimps and dry them with kitchen towel.
Zest a large lemon and then squeeze the juice to give at least 2 tablespoons of juice and close to half a tablespoon of lemon zest. Clean the garlic and finely chop it.
Heat the olive oil in medium to high heat, then add the butter to melt.
Add the shrimps to a single layer and leave until they start getting pink color at the edges, no longer than 1-2 minutes.
Turn the shrimps on the other side and add the chopped garlic. Continue cooking for another 3-4 minutes. Pour in the lemon juice, add the lemon zest and salt to taste and mix to cover the shrimps with the sauce.