SELECT 
  cscart_product_features.feature_id, 
  cscart_product_features.feature_code, 
  cscart_product_features.company_id, 
  cscart_product_features.feature_type, 
  cscart_product_features.parent_id, 
  cscart_product_features.display_on_product, 
  cscart_product_features.display_on_catalog, 
  cscart_product_features.display_on_header, 
  cscart_product_features_descriptions.description, 
  cscart_product_features_descriptions.internal_name, 
  cscart_product_features_descriptions.lang_code, 
  cscart_product_features_descriptions.prefix, 
  cscart_product_features_descriptions.suffix, 
  cscart_product_features.categories_path, 
  cscart_product_features_descriptions.full_description, 
  cscart_product_features.status, 
  cscart_product_features.comparison, 
  cscart_product_features.position, 
  cscart_product_features.purpose, 
  cscart_product_features.feature_style, 
  cscart_product_features.filter_style 
FROM 
  cscart_product_features 
  LEFT JOIN cscart_product_features_descriptions ON cscart_product_features_descriptions.feature_id = cscart_product_features.feature_id 
  AND cscart_product_features_descriptions.lang_code = 'en' 
WHERE 
  cscart_product_features.feature_id = 999

Query time 0.00097

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "1.00"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_features",
          "access_type": "const",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "feature_id"
          ],
          "key_length": "3",
          "ref": [
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.20",
            "prefix_cost": "0.00",
            "data_read_per_join": "440"
          },
          "used_columns": [
            "feature_id",
            "feature_code",
            "company_id",
            "purpose",
            "feature_style",
            "filter_style",
            "feature_type",
            "categories_path",
            "parent_id",
            "display_on_product",
            "display_on_catalog",
            "display_on_header",
            "status",
            "position",
            "comparison"
          ]
        }
      },
      {
        "table": {
          "table_name": "cscart_product_features_descriptions",
          "access_type": "const",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "feature_id",
            "lang_code"
          ],
          "key_length": "9",
          "ref": [
            "const",
            "const"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.00",
            "eval_cost": "0.20",
            "prefix_cost": "0.00",
            "data_read_per_join": "2K"
          },
          "used_columns": [
            "feature_id",
            "description",
            "full_description",
            "prefix",
            "suffix",
            "lang_code",
            "internal_name"
          ]
        }
      }
    ]
  }
}