If u are two person's then I would suggest train 1 AC - coach type should be coup as you will get seperate room kind structure for with lower and upper birth so you would be isolated from everyone else. Flight might take very less time but u will have to sit with others so chances are high to get infected.
One more this in 1 AC , you will get 2 options, cabin and coop so cabin have 4 and coop have 2 births.