Finally found the solution. I have added a property owsmetadatafacetinfo to keyword query:

var properties = keywordQuery.get_selectProperties();
properties.add('owsmetadatafacetinfo');

Then in the query results, I got the null if managed metadata column does not exist for search result.

If metadata column exist then, I got it with column & it's value for current search result with property owsmetadatafacetinfo :

function onQuerySuccess() {
    $.each(results.m_value.ResultTables[0].ResultRows, function () {

        console.log(this.Title + ' - ' + this.Author);

        /* Following will return value like:
           > Carx0020Filter|Car Filter|kpEc4Tt0Bk6aYzIoWUkAng==|YS6tyhuAgUWauGGOBUO7Hg==|#d317325c-2705-4006-8158-eea6f2629618|Lamborghini;#"             
           Here, 'Car Filter' is managed metadata column & 'Lamborghini' is value for current search result */
        
          console.log(this.owsmetadatafacetinfo);

    });    
}

It's return like:

Carx0020Filter|Car Filter|kpEc4Tt0Bk6aYzIoWUkAng==|YS6tyhuAgUWauGGOBUO7Hg==|#d317325c-2705-4006-8158-eea6f2629618|Lamborghini;#"

Where, Car Filter is managed metadata column (with internal name Carx0020Filter) & Lamborghini is value for current search result.

Finally, find the solution. I have added a property owsmetadatafacetinfo to keyword query:

var properties = keywordQuery.get_selectProperties();
properties.add('owsmetadatafacetinfo');

Then in the query results, I got the null if managed metadata column does not exist for search result.

If metadata column exist then, I got it with column & it's value for current search result with property owsmetadatafacetinfo :

function onQuerySuccess() {
    $.each(results.m_value.ResultTables[0].ResultRows, function () {

        console.log(this.Title + ' - ' + this.Author);

        /* Following will return value like:
           > Carx0020Filter|Car Filter|kpEc4Tt0Bk6aYzIoWUkAng==|YS6tyhuAgUWauGGOBUO7Hg==|#d317325c-2705-4006-8158-eea6f2629618|Lamborghini;#"             
           Here, 'Car Filter' is managed metadata column & 'Lamborghini' is value for current search result */
        
          console.log(this.owsmetadatafacetinfo);

    });    
}

It's return like:

Carx0020Filter|Car Filter|kpEc4Tt0Bk6aYzIoWUkAng==|YS6tyhuAgUWauGGOBUO7Hg==|#d317325c-2705-4006-8158-eea6f2629618|Lamborghini;#"

Where, Car Filter is managed metadata column (with internal name Carx0020Filter) & Lamborghini is value for current search result.

Finally found the solution. I have added a property owsmetadatafacetinfo to keyword query:

var properties = keywordQuery.get_selectProperties();
properties.add('owsmetadatafacetinfo');

Then in the query results, I got the null if there is no any managed metadata column exist for search result.

If metadata column exist then, I got it with column & it's value for current search result with property owsmetadatafacetinfo :

function onQuerySuccess() {
    $.each(results.m_value.ResultTables[0].ResultRows, function () {

        console.log(this.Title + ' - ' + this.Author);

        /* Following will return value like:
           > Carx0020Filter|Car Filter|kpEc4Tt0Bk6aYzIoWUkAng==|YS6tyhuAgUWauGGOBUO7Hg==|#d317325c-2705-4006-8158-eea6f2629618|Lamborghini;#"             
           Here, 'Car Filter' is managed metadata column & 'Lamborghini' is value for current search result */
        
          console.log(this.owsmetadatafacetinfo);

    });    
}

It's return like:

Carx0020Filter|Car Filter|kpEc4Tt0Bk6aYzIoWUkAng==|YS6tyhuAgUWauGGOBUO7Hg==|#d317325c-2705-4006-8158-eea6f2629618|Lamborghini;#"

Where, Car Filter is managed metadata column (with internal name Carx0020Filter) & Lamborghini is value for current search result.

Finally found the solution. I have added a property owsmetadatafacetinfo to keyword query:

var properties = keywordQuery.get_selectProperties();
properties.add('owsmetadatafacetinfo');

Then in the query results, I got the null if managed metadata column does not exist for search result.

If metadata column exist then, I got it with column & it's value for current search result with property owsmetadatafacetinfo :

function onQuerySuccess() {
    $.each(results.m_value.ResultTables[0].ResultRows, function () {

        console.log(this.Title + ' - ' + this.Author);

        /* Following will return value like:
           > Carx0020Filter|Car Filter|kpEc4Tt0Bk6aYzIoWUkAng==|YS6tyhuAgUWauGGOBUO7Hg==|#d317325c-2705-4006-8158-eea6f2629618|Lamborghini;#"             
           Here, 'Car Filter' is managed metadata column & 'Lamborghini' is value for current search result */
        
          console.log(this.owsmetadatafacetinfo);

    });    
}

It's return like:

Carx0020Filter|Car Filter|kpEc4Tt0Bk6aYzIoWUkAng==|YS6tyhuAgUWauGGOBUO7Hg==|#d317325c-2705-4006-8158-eea6f2629618|Lamborghini;#"

Where, Car Filter is managed metadata column (with internal name Carx0020Filter) & Lamborghini is value for current search result.