SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f5a9c7a691ae2361c289bf88e62cb79864247fa978c602e33b1d7ce7395aa37' 
  AND token = 'hTGco/0mGjvRo78THOJuJLjfawPxICR++1pFWCyU6vU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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