SELECT 
  gallery_id 
FROM 
  cscart_image_gallery_ext_settings 
WHERE 
  FIND_IN_SET(162, products)

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}