SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70fc82a7869fc2d3fc950252961d259224932d09b25cf8ebf92bfaba50a2cc1f' 
  AND token = '5nZciZmJxGr4gYzUssRH8FeLBCozG00zlGVIeFPEjNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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