SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '523f66daeec110fb87a90268bbc0691535af427e218fe64a3bcee90f7ab49376' 
  AND token = 'Z5Yc/kLWCNfY+VbHmrlDR3uOkpdvoOxY5P6ApVhoRhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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