SELECT 
  default_view_desktop 
FROM 
  tmall_categories 
WHERE 
  category_id = 223 
  AND selected_views != ""

Query time 0.00808

JSON explain

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