SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '785fee533e93673c0dc0406312b7411405854f2cc7176e26f17f23ff46e34b36' 
  AND token = 'YwZwvnGA04cObKXw69q7PhLoPKZ5UNXaqBxmFwxY8Ds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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