Marlin appears to support older versions of the board (and possibly this one) according to this line

#define BOARD_MKS_13            47   // MKS v1.3 or 1.4 (maybe higher)

in boards.h which can be found here.

The company also has a guide and looks to provide pre-configured (but not fully configured?) downloads of Marlin. They have different links for different displays but then ask you to change lines manually but don't mention changing the board so I have no idea what they are doing or what is different between the downloads.

It appears either way you go (Marlin from Github or from Osoyoo) you will need to change some lines to get each axis to behave correctly.

A more recent version of Marlin Firmware (version 1.1.9 is the last release of this branch, new developments are done in the 2.x branch) nowadays has a separate board constant for the MKS BASE v1.5 board (BOARD_MKS_BASE_15) as can be found in boards.h.

The following line quotes the constant for this board from the file:

#define BOARD_MKS_BASE_15 405 // MKS v1.5 with Allegro A4982 stepper drivers