Yes. The USB MEMORY/EXT DEVICE port (USB Type-A) on the GAIA-2 supports the connection of MIDI keyboards compatible with generic drivers.
*You cannot connect to the USB COMPUTER port (USB Type-C®).
Any MIDI keyboard with a current consumption of 500 mA or less for USB connection, such as the Roland A series, can obtain power from the GAIA-2.
For details on connection methods and precautions, see "GAIA-2 Reference Manual".