SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2741233daf5c9864b0ff89e0892ddc0f2e1ebc9cac63b366fd88e734a80538c4' 
  AND token = '6CvTgxy63RnEVXlWH0Tj77MAPgY0pLJKh8l+EicBbDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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