Callback async

exports.validateImport = async (req, res) => {
    let mysql = require('mysql');

    let con = mysql.createConnection({
        host: "localhost",
        user: "root",
        password: "root",
        database: "db_dev_indoacc"
    });

    con.connect(function (err) {
        if (err) throw err;
    });

    let importData = req.body.excel;

    let validated = [];

    let validate = (callback) => {
        for (let i = 0; i < importData.length; i++) {
            let goodsNotExists = (callback) => {
                con.query("SELECT mgoodscode, mgoodsname FROM mgoods WHERE mgoodscode = ? AND mgoodsname= ? AND void = 0",
                    [importData[i]['Kode Barang'], importData[i]['Nama Barang']], (error, rows, fields) => {
                        if (error) {
                            return callback(error);
                        } else {
                            if (rows.length === 0) {
                                callback(null, importData[i]);
                            }
                        }
                    }
                )
            };

            goodsNotExists((err, data) => {
                if (err) {
                    return callback(err)
                } else {
                    callback(null, data)
                }
            })
        }
    };

    validate((err, data) => {
        if(err){
            console.log('Err');
        } else {
            validated.push(data);
        }
    });

    setTimeout(() => {
        res.json(validated);
    }, 50)
};