A squirrel cage induction motor operating from a VFD is considered to be constant torque below the base speed (2950 rpm) and constant kW above the base speed.

One other caution, which you seem to already be aware of, is the influence of affinity laws on speed when applying variable torque loads such as pumps or blowers. As long as the pump requires 90 kW at 3550 rpm, a 90 kW is sufficient for the task.