Product attribute schema design, mixing solutions
Put common things (price, SKU) in MySQL columns; index them if needed.

Put the rest in a JSON column.  Do not try to use LIKE to search that.

Instead, first filter on what you can from the other columns, then use your application language to finish the filtering.

To save on space and bandwidth, compress (in the client) the JSON string and put it into a BLOB column.

Write your user-interface to encourage them to filter on the real columns, only reluctantly let them specify the other things.

See also MariaDB's "Dynamic Columns; it's been available for several releases.  In the future, 5.7 promises to have a bunch of JSON tools.