How to use query operation with app sync auto generated resolver? - amazon-web-services

Question

Below is the autogenerated resolver of appsync with DynamoDB. I am unable to understand what object I have to pass to use the Query operation.
#set( $limit = $util.defaultIfNull($context.args.limit, 100) )
#set( $ListRequest = {
"version": "2018-05-29",
"limit": $limit
} )
#if( $context.args.nextToken )
#set( $ListRequest.nextToken = $context.args.nextToken )
#end
#if( $context.args.filter )
#set( $ListRequest.filter = $util.parseJson("$util.transform.toDynamoDBFilterExpression($ctx.args.filter)") )
#end
#if( !$util.isNull($modelQueryExpression)
&& !$util.isNullOrEmpty($modelQueryExpression.expression) )
$util.qr($ListRequest.put("operation", "Query"))
$util.qr($ListRequest.put("query", $modelQueryExpression))
#if( !$util.isNull($ctx.args.sortDirection) && $ctx.args.sortDirection == "DESC" )
#set( $ListRequest.scanIndexForward = false )
#else
#set( $ListRequest.scanIndexForward = true )
#end
#else
$util.qr($ListRequest.put("operation", "Scan"))
#end
$util.toJson($ListRequest)
I have tried to pass the below query but got the all data of table. I have also tried with simple filter scan it's working and returning the data but I want to use index.
let modelQueryExpression = {
"expression": "#bookingtype = :bookingtype AND #bookinguserid = :bookinguserid",
"expressionNames": {
"#bookinguserid": "bookinguserid",
"#bookingtype": "bookingtype",
},
"expressionValues": {
":bookingtype": {
"S": JSON.parse(user).id,
},
":parent": {
"S": 'Trip',
},
}
}
const bookingdata = await API.graphql({ query: listBookings, variables: { modelQueryExpression } });