SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '799e243eae5fe226cce1e2054c57e5cb4d1051480cb77e0697017340e8c870c1' 
  AND token = '5mrbr5gN+NoEa2KddX6GbttrqKqrqufaZOmiJ7oqESk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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