The main requirement is not a long exposure — it’s something in the air to scatter the light: dust, smoke, haze, mist, or water droplets. To make the beams stand out, you also want the light source to be much brighter than the surroundings, and ideally a darker background behind the beams.

So the recipe is:

• strong directional light from the window
• particles in the air
• darker ambient exposure/background for contrast

A tripod/long exposure is only optional. Use it if the room is very dark, but the beams themselves can be visible at normal shutter speeds. In your example, the long exposure likely explains the ghosted people, not the existence of the light shafts.

To replicate it reliably indoors, wait for strong sunlight and look for naturally dusty or hazy air; mist or steam can also demonstrate the effect. Expose for the bright window light so the room goes relatively dark, which helps the shafts separate from the background. Some post-processing contrast/dodging may enhance the look, but the effect should be created in-camera by light plus airborne particles.