SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c317f303bfd97dfea9966aa0f64616704013a8a052a560dcb7ad62829094663' 
  AND token = 'I9oWW/7sibfdt4XuwARyKPZ4zESUBKucKtxbdmVizb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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