SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f535602edf30ab2c7b9b1da54f12b06a3371353c07c658c61bfd0bad684fb59' 
  AND token = 'xYU/inpBU1uzQlO5alQhEmIJZDHdR+Wp+DgmhhEd0U4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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