There is an easy solution for this if you are running OBS on the Windows platform. 

You will need to create a .bat file (I called mine Start_OBS.bat and in that file, place the below text.

cd "C:\Program Files\obs-studio\bin\64bit\"

start "OBSSTUDIO" "C:\Program Files\obs-studio\bin\64bit\obs64.exe"

Once you have that created, I placed mine on my desktop. You can place it where ever your would like. 

Follow the below instructions to assign it to a Quick Keys Button. 

I selected Button 8 to press when I wanted to start OBS.

[1] Select your Quick Keys from the left-hand navigation. If you only have the Quick Keys, that will be your only select option.

[2] Click the button you want to assign the action to. In this case, it is button 8 - it is hard to see that.

[3] Select Application, [4] choose Open/Run from the menu.

In the Application selection menu [1], Browse

This will open the file explorer, and you will need to [2] navigate to the DeskTop or the location in which you placed the .bat file.

[3] Once in the folder, you will need to change the file type to All Files. By default, it is set to .exe.

[4] Select the .bat file

[5] Once selected, it will appear in the File name viewer.

[6] Select Open

[1] This shows you the file location.

[2] It auto assigns a name that will be displayed on the Quick Keys OLED.

[3] Select Ok, and this will complete the setup.

This shows the setup on the OLED for [1] button 8 that will open the OSB application when pressed.