SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a740c7d47267e2d8195c7a556fe61f384fcdc9c2cb99b17a7b85c3226fc3190' 
  AND token = '+s6m7Ua8XNjBQCcTNj5rh9JYN9BhvkzIhMI9K+ZxXCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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