SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b1e0a9209ff471a8e7ee95c6a304bfa5364884ac86e3816e72feecd8a9f7de5f' 
  AND token = 'fd3T5YzE7hr8m7jTkZLncvhYFRixmqjFeDjwuu+ISKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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