SELECT 
  cscart_product_reviews.*, 
  cscart_users.company_id as reply_company_id, 
  cscart_companies.company as reply_company, 
  cscart_country_descriptions.country as country 
FROM 
  cscart_product_reviews 
  LEFT JOIN cscart_users ON cscart_product_reviews.reply_user_id = cscart_users.user_id 
  LEFT JOIN cscart_companies ON cscart_users.company_id = cscart_companies.company_id 
  LEFT JOIN cscart_country_descriptions ON cscart_product_reviews.country_code = cscart_country_descriptions.code 
  AND cscart_country_descriptions.lang_code = 'en' 
WHERE 
  1 
  AND cscart_product_reviews.product_id IN (5999) 
  AND cscart_product_reviews.status = 'A' 
ORDER BY 
  cscart_product_reviews.product_review_timestamp desc 
LIMIT 
  0, 10

Query time 0.00075

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "read_sorted_file": {
          "filesort": {
            "sort_key": "cscart_product_reviews.product_review_timestamp desc",
            "table": {
              "table_name": "cscart_product_reviews",
              "access_type": "ref",
              "possible_keys": ["idx_product_id"],
              "key": "idx_product_id",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["const"],
              "rows": 5,
              "filtered": 100,
              "attached_condition": "cscart_product_reviews.product_id <=> 5999 and cscart_product_reviews.`status` = 'A'"
            }
          }
        }
      },
      {
        "table": {
          "table_name": "cscart_users",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["user_id"],
          "ref": ["dev_db.cscart_product_reviews.reply_user_id"],
          "rows": 1,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "cscart_companies",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "4",
          "used_key_parts": ["company_id"],
          "ref": ["dev_db.cscart_users.company_id"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "trigcond(trigcond(cscart_users.company_id is not null))"
        }
      },
      {
        "table": {
          "table_name": "cscart_country_descriptions",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "12",
          "used_key_parts": ["code", "lang_code"],
          "ref": ["dev_db.cscart_product_reviews.country_code", "const"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "trigcond(cscart_country_descriptions.lang_code = 'en')"
        }
      }
    ]
  }
}