SELECT 
  link_id 
FROM 
  cscart_cp_seo_links 
WHERE 
  type = 'P' 
  AND object_id = 5556 
  AND lang_code = 'en'

Query time 0.00016

JSON explain

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