SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd0578203e9efa7c961b731bbc3015aa8d9cbd59da0029d7c2339f4785baff28' 
  AND token = 'v2eey+ZqzQhUY/x2UPuuAoQwHtCqGfk+KvLqf8YhD9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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