SELECT 
  et_menu_id, 
  categ_id, 
  size, 
  thumbnails, 
  icon, 
  text, 
  banner, 
  products 
FROM 
  cscart_et_category_menu 
WHERE 
  1 
  AND cscart_et_category_menu.lang_code = 'en' 
  AND cscart_et_category_menu.categ_id IN (
    266, 2374, 445, 1939, 443, 1936, 2178, 
    2373, 2591
  )

Query time 0.00093

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.61"
    },
    "table": {
      "table_name": "cscart_et_category_menu",
      "access_type": "range",
      "possible_keys": [
        "categ_id"
      ],
      "key": "categ_id",
      "used_key_parts": [
        "categ_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 9,
      "rows_produced_per_join": 9,
      "filtered": "100.00",
      "index_condition": "((`webmarco`.`cscart_et_category_menu`.`lang_code` = 'en') and (`webmarco`.`cscart_et_category_menu`.`categ_id` in (266,2374,445,1939,443,1936,2178,2373,2591)))",
      "cost_info": {
        "read_cost": "19.81",
        "eval_cost": "1.80",
        "prefix_cost": "21.61",
        "data_read_per_join": "720"
      },
      "used_columns": [
        "et_menu_id",
        "categ_id",
        "size",
        "thumbnails",
        "icon",
        "text",
        "banner",
        "lang_code",
        "products"
      ]
    }
  }
}

Result

et_menu_id categ_id size thumbnails icon text banner products
3 266 a:2:{s:5:"width";s:1:"0";s:6:"height";s:1:"0";} a:1:{s:7:"enabled";s:1:"Y";} a:5:{s:7:"enabled";s:1:"Y";s:4:"type";s:1:"G";s:5:"value";s:26:" fa fa-fw fa-heart";s:10:"color_type";s:1:"S";s:5:"color";s:7:"#ffffff";} a:6:{s:7:"enabled";s:1:"N";s:5:"label";s:0:"";s:10:"color_type";s:1:"S";s:5:"color";s:7:"#ffffff";s:3:"bkg";s:7:"#000000";s:5:"descr";s:0:"";} a:5:{s:7:"enabled";s:1:"N";s:3:"url";s:0:"";s:9:"push_menu";s:1:"N";s:12:"offset_right";s:1:"0";s:13:"offset_bottom";s:1:"0";} a:13:{s:7:"enabled";s:1:"N";s:8:"position";s:1:"R";s:10:"show_title";s:1:"Y";s:5:"title";s:0:"";s:10:"color_type";s:1:"S";s:21:"title_bkg_transparent";s:1:"N";s:9:"title_bkg";s:7:"#000000";s:11:"title_color";s:7:"#ffffff";s:19:"show_discount_label";s:1:"Y";s:9:"show_name";s:1:"Y";s:10:"show_price";s:1:"Y";s:14:"show_old_price";s:1:"Y";s:7:"content";a:1:{s:5:"items";a:1:{s:7:"filling";s:8:"manually";}}}
61275 443 a:4:{s:7:"enabled";s:1:"N";s:5:"label";s:0:"";s:5:"color";s:7:"#ffffff";s:3:"bkg";s:7:"#000000";}
237933 445 a:4:{s:7:"enabled";s:1:"N";s:5:"label";s:0:"";s:5:"color";s:7:"#ffffff";s:3:"bkg";s:7:"#000000";}
61284 1936 a:4:{s:7:"enabled";s:1:"N";s:5:"label";s:0:"";s:5:"color";s:7:"#ffffff";s:3:"bkg";s:7:"#000000";}
239235 2591 a:4:{s:7:"enabled";s:1:"N";s:5:"label";s:0:"";s:5:"color";s:7:"#ffffff";s:3:"bkg";s:7:"#000000";}