SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '726f0d914815c4b622cd6457e9febcfb912daf1740f918962a437000211e5fca' 
  AND token = '03maWpEKU4OjZdrdEr3yq7/zCs9cWchZ5IonLi6Qxyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}