Only records that satisfy the expression will be returned so please make sure your query is correct. what does a simple select query return? Try this and check -
select * from LogTable
If you are not getting any hits then please specify the region end point.
and if it returns then please make sure the condition you have specified is getting matched.
Edited :
Please try to run this code and specify region end point using this link to which your domain belongs.
AmazonSimpleDBConfig theConfig = new AmazonSimpleDBConfig();
theConfig.ServiceURL = myEndpoint; //where myEndPoint is the region endpoint you are interested in
AmazonSimpleDBClient simpleDbClient= new AmazonSimpleDBClient(myKey, mySecretKey, theConfig);
String selectExpression = "select * from LogTable";
SelectRequest selectRequestAction = new SelectRequest();
selectRequestAction.SelectExpression = selectExpression;
selectRequestAction.NextToken = null;
SelectResponse selectResponse = simpleDbClient.Select(selectRequestAction);
SelectResult selectResult = selectResponse.SelectResult;
List<Item> itemList = selectResult.Item;