SELECT 
  products.company_id, 
  COUNT(DISTINCT products.product_id) as products_count 
FROM 
  cscart_products as products 
  LEFT JOIN cscart_product_descriptions as descr1 ON descr1.product_id = products.product_id 
  AND descr1.lang_code = 'en' 
  LEFT JOIN cscart_product_prices as prices ON prices.product_id = products.product_id 
  AND prices.lower_limit = 1 
  LEFT JOIN cscart_companies AS companies ON companies.company_id = products.company_id 
  INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  AND cscart_categories.storefront_id IN (0, 1) 
WHERE 
  1 = 1 
  AND companies.status IN ('A') 
  AND products.status IN ('A') 
  AND (
    products.usergroup_ids = '' 
    OR FIND_IN_SET(0, products.usergroup_ids) 
    OR FIND_IN_SET(1, products.usergroup_ids)
  ) 
  AND products.status IN ('A') 
  AND prices.usergroup_id IN (0, 0, 1) 
  AND products.parent_product_id = 0 
  AND products.product_type != 'D' 
  AND products.company_id IN (2) 
GROUP BY 
  products.company_id

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "companies",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "4",
      "used_key_parts": ["company_id"],
      "ref": ["const"],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "products",
      "access_type": "ref",
      "possible_keys": ["PRIMARY", "status", "idx_parent_product_id"],
      "key": "status",
      "key_length": "3",
      "used_key_parts": ["status"],
      "ref": ["const"],
      "rows": 2,
      "filtered": 100,
      "index_condition": "products.`status` = 'A'",
      "attached_condition": "products.parent_product_id = 0 and products.company_id = 2 and (products.usergroup_ids = '' or find_in_set(0,products.usergroup_ids) or find_in_set(1,products.usergroup_ids)) and products.product_type <> 'D'"
    },
    "table": {
      "table_name": "prices",
      "access_type": "ref",
      "possible_keys": ["usergroup", "product_id", "lower_limit", "usergroup_id"],
      "key": "usergroup",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "ref": ["fluentmart_cscart.products.product_id"],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "prices.lower_limit = 1 and prices.usergroup_id in (0,0,1)",
      "using_index": true
    },
    "block-nl-join": {
      "table": {
        "table_name": "products_categories",
        "access_type": "index",
        "possible_keys": ["PRIMARY", "pt"],
        "key": "PRIMARY",
        "key_length": "6",
        "used_key_parts": ["category_id", "product_id"],
        "rows": 3,
        "filtered": 100,
        "using_index": true
      },
      "buffer_type": "flat",
      "buffer_size": "8Kb",
      "join_type": "BNL",
      "attached_condition": "products_categories.product_id = products.product_id"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY", "c_status", "p_category_id"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["category_id"],
      "ref": ["fluentmart_cscart.products_categories.category_id"],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "(cscart_categories.usergroup_ids = '' or find_in_set(0,cscart_categories.usergroup_ids) or find_in_set(1,cscart_categories.usergroup_ids)) and cscart_categories.`status` in ('A','H') and cscart_categories.storefront_id in (0,1)"
    }
  }
}