No way hydro lock can happen due to car wash.
Firstly, what is hydrolock? Well, it happens when an incompressible liquid enters the combustion cylinder. Lets take water as an example. So the cylinder fills with water and when the piston moves up, the water, being incompressible, prevents the movement. However, piston is in motion and other cylinders may be firing, so something has to give. Either the combustion cavity has to break I.e. gasket failure or the connecting rod connecting the piston to the crank should break. That's a hydrostatic failure.
Point is, fuel air mixture is compressible. That compression gives the power. From what you did prior to the failure, only water or oil leak into the cylinder could have caused this. But if you wash your car, water cant enter the engine in any way other because there is no direct route.
There is only one possibility- water entering your fuel tank. If this happens, water will sit at the bottom, and petrol, being lighter than water will float on top. The fuel pick up is at the bottom, so water will then be drawn into the engine. Usually, there is some fuel in the line connecting the fuel pump to the engine, so the engine will start initially and then, once the water reaches the engine, it will stall and will refuse to start. Hydrostatic pressure is very unlikely.
Check if your filler cap was not in place whilst the car was washed. If so, ask the ASC to drain the fuel tank into a tub and show you the contents. If you see water there, thats the real culprit. If so, you should ask the car wash how the water got in. If not, its quite perplexing
Ameyam