Sandbox

SELECT 
  ctl.object_id as video_id, 
  GROUP_CONCAT(
    DISTINCT ct.tag 
    ORDER BY 
      ct.tag ASC SEPARATOR ', '
  ) as tags 
FROM 
  cscart_tag_links ctl 
  LEFT JOIN cscart_tags ct ON ct.tag_id = ctl.tag_id 
WHERE 
  ctl.object_id IN (845, 987, 1123, 1350, 2115) 
GROUP BY 
  ctl.object_id

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "34.86"
    },
    "grouping_operation": {
      "using_filesort": false,
      "nested_loop": [
        {
          "table": {
            "table_name": "ctl",
            "access_type": "range",
            "possible_keys": [
              "PRIMARY",
              "ids",
              "idx_tag_links_object_id"
            ],
            "key": "idx_tag_links_object_id",
            "used_key_parts": [
              "object_id"
            ],
            "key_length": "4",
            "rows_examined_per_scan": 42,
            "rows_produced_per_join": 42,
            "filtered": "100.00",
            "index_condition": "(`cscart_db`.`ctl`.`object_id` in (845,987,1123,1350,2115))",
            "cost_info": {
              "read_cost": "15.96",
              "eval_cost": "4.20",
              "prefix_cost": "20.16",
              "data_read_per_join": "672"
            },
            "used_columns": [
              "tag_id",
              "object_id"
            ]
          }
        },
        {
          "table": {
            "table_name": "ct",
            "access_type": "eq_ref",
            "possible_keys": [
              "PRIMARY"
            ],
            "key": "PRIMARY",
            "used_key_parts": [
              "tag_id"
            ],
            "key_length": "3",
            "ref": [
              "cscart_db.ctl.tag_id"
            ],
            "rows_examined_per_scan": 1,
            "rows_produced_per_join": 42,
            "filtered": "100.00",
            "cost_info": {
              "read_cost": "10.50",
              "eval_cost": "4.20",
              "prefix_cost": "34.86",
              "data_read_per_join": "32K"
            },
            "used_columns": [
              "tag_id",
              "tag"
            ]
          }
        }
      ]
    }
  }
}

Result

video_id	tags
845	#Glowing Skin, #kbeauty, #kindlifeapproved, #nourishing, #serum, #Skin Hydration, #Skin Repair, #skincare, #soothing
987	#Glowing Skin, #hydrating, #kbeauty, #kindlifeapproved, #nourishing, #serum, #Skin Repair, #skincare, #soothing, all skin types, brightening, Even Skin Tone, Lifestyle Concerns, Skin Hydration
1123	#all skin types, #brightening, #dark spots, #Dull Skin, #Even Skin Tone, #kbeauty, #kindlifeapproved, #korean beauty, #KOREAN SKINCARE, #Skin Hydration
1350	#cleanser, #hydrating skin, #kindlife, #skincare, #skinhydration, #summerskincare, #sunscreen, #toner