We could make a quantitative comparison using some ballpark figures.
Power consumption of your car's air conditioner depends on many factors, including its settings and the environment. A fair assumption of average consumption is approximately 3 kW (which might be as much as a factor of 2 off). This number can be compared with The increase of air drag power losses by opening windows.
Air drag power losses can approximately be calculated as P = ½ ρ C A v3, with ρ the air density, C the vehicle air drag coefficient, A the vehicle frontal surface area and v the vehicle velocity. We have ρ = 1.225 k/m³ and v = 130/3.6 km/h = 36.111 m/s. A and C largely depend on the car type. For a modern car (sedan) we have C A ≈ 0.3×1.8 = 0.54 and for an MPV/SUV C·A ≈ 0.45×3 = 1.35. We find P = 15.7 kW and P = 38.9 kW for respectively the sedan and MPV. The next question is: how do these figures increase if windows are opened? A study has shown that power losses increase with ca. 8% and 20% for sedans and SUVs respectively. Notably, this difference in percent seems to scale inversely linear to C A, suggesting that the increased losses are not so much a function of the car's shape. This makes sense: car windows have approximately the same size in both big and small cars, and opening them does not change your car's frontal shape. It follows that the increased losses can be roughly described by Δ P = ½ ρ 0.108 v3, for which we find 3.1 kW (for 130 km/h), approximately the same as the 3 kW figure of the air conditioner!
Be reminded that various of the above figures are very rough, including the 3kW figure of the air conditioner. As such, we cannot come to an obvious conclusion. However, also note that air drag increases cubically with speed. It will likely be safe to say that, for speeds under 100 km/h (ca. halve the drag) open windows will win, and for speed above 160 km/h (ca. double the drag) the air conditioner will win. Anyway, as others have mentioned, for higher speeds (>80 km/h), other issues will become more prominent, such as noise, for which closed windows might nevertheless be preferred.