Launchy is a classic program launcher for Windows.
Install: It can be downloaded and installed from here.
Launch: Once it is running in the background, it can launched anytime by pressing Alt + Space. This shortcut can be changed in its Options.
Scale to high DPI: I found that Launchy looked tiny on my high DPI Windows 10 system. To make it look a normal size, I opened the Properties on C:\Program Files (x86)\Launchy\Launchy.exe. Here I chose Compatibility -> Change DPI settings and under High DPI Scaling Override chose System.
Tried with: Launchy 2.5 and Windows 10 x64