It appears that once the device has hit the EOL list, you can no longer purchase licenses.
However I suggest you reach out to your Meraki SE or partner to confirm, especially if you need a license to bridge the gap between now and replacement.
On the EOS Date, discontinued hardware products are removed from the price list and are no longer available for purchase. The device-specific licenses corresponding to discontinued hardware products will be available for purchase after the EOS Date, unless the license(s) is/are listed in the “End-of-Life Products” list provided below.
Support Policies | Cisco Meraki