Hi,
USB works in differential mode, this is the opposite to common mode.
So the values of impedance and frequency are independent for both modes.
The common mode chokes are made to have low influence of differential mode signals. They pass the USB signal with a series impedance (probably dominated by resistance) with way lower than 90 Ohms at 240MHz.
In common mode they represent an increasing impedance with increasing (common mode) frequency. So common mode noise above 240MHz will be suppressed, while the differential USB signals will pass.
Klaus