As others have mentioned, the numbers on the tire is the maximum pressure. The "best" tire pressure is going to differ between individuals based on our weight, riding style, and typical road conditions. Too much pressure, especially on skinnier tires, translates to a rougher ride, too little pressure makes us more liable to pinch flats.

You might want to conduct a few test rides over the same route with different pressures to see what pressure works best for you. Pick a 1-2 mile route that you know well, no surprises regarding pavement condition. Drop your pressure 5 pounds each time between each lap to see what that feels like. I wouldn't drop it below 90 myself, but I don't know much about skinny tires. I use 70 psi, but I don't ride high pressure skinny tires either.

Also check your tire pressure before every ride - not all seem to but I credit this practice to not having a flat in about 2 years and 3 months of riding - which is as long as I've been riding so I've never had one. Yet.