How about this?
RandomEntity[
EntityClass["City", "Area" -> Quantity[Interval[{0, Infinity}], "Miles"*"Miles"]], 4] //
EntityValue[#, {"Area"}, "EntityAssociation"] & //AbsoluteTiming
(*
{1.70067,
<|Entity["City", {"Westminster", "Colorado", "UnitedStates"}] -> {Quantity[31.550416264, ("Miles")^2]},
Entity["City", {"Belvue", "Kansas", "UnitedStates"}] -> {Quantity[0.115757288, ("Miles")^2]},
Entity["City", {"Lewisville", "Indiana", "UnitedStates"}] -> {Quantity[0.253491511, ("Miles")^2]},
Entity["City", {"Lehighton", "Pennsylvania", "UnitedStates"}] -> {Quantity[1.623076949,("Miles")^2]}|>}
*)