If you keep your crickets in a tank, you could try putting the entire tank into a larger shallow pan of water to create a moat that the ants will hopefully drown in. Also, you can try applying some double-faced tape completely around the tank slightly above the water level of the pan, in a wide band, to provide a second level of defense that acts similarly to roach motels.

If the cricket enclosure sits on a table with legs, try standing the legs in containers of water.

Put out a lot of ant traps, especially in their paths.

Disrupt as many of the paths possible, that the ants use to reach your crickets.