SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35bcdd518dad1edcc156ad46708b27177fb5e6fc8fa827999628605d8297f363' 
  AND token = 'PMuHmRD3wVzGiQWqt/LDKeBnOjtwLXMTl5YFbhef8B8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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