SELECT 
  cscart_payments.*, 
  cscart_payment_descriptions.*, 
  IF (
    ISNULL(cscart_addons.status), 
    "A", 
    cscart_addons.status
  ) AS processor_status, 
  cscart_payment_processors.type AS processor_type, 
  cscart_payment_processors.processor_script AS processor_script 
FROM 
  cscart_payments 
  LEFT JOIN cscart_payment_descriptions ON cscart_payment_descriptions.payment_id = cscart_payments.payment_id 
  AND cscart_payment_descriptions.lang_code = 'ru' 
  LEFT JOIN cscart_payment_processors ON cscart_payment_processors.processor_id = cscart_payments.processor_id 
  LEFT JOIN cscart_addons ON cscart_payment_processors.addon = cscart_addons.addon 
  LEFT JOIN cscart_storefronts_payments AS storefronts_payments ON storefronts_payments.payment_id = cscart_payments.payment_id 
WHERE 
  cscart_payments.status = 'A' 
  AND (
    cscart_payments.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_payments.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_payments.usergroup_ids
    )
  ) 
  AND (
    storefronts_payments.storefront_id = 1 
    OR storefronts_payments.storefront_id IS NULL
  ) 
HAVING 
  processor_status = 'A' 
ORDER BY 
  cscart_payments.position

Query time 0.00485

JSON explain

{
  "query_block": {
    "select_id": 1,
    "having_condition": "processor_status = 'A'",
    "filesort": {
      "sort_key": "cscart_payments.position",
      "temporary_table": {
        "table": {
          "table_name": "cscart_payments",
          "access_type": "ALL",
          "possible_keys": ["c_status"],
          "rows": 9,
          "filtered": 100,
          "attached_condition": "cscart_payments.`status` = 'A' and (cscart_payments.usergroup_ids = '' or find_in_set(0,cscart_payments.usergroup_ids) or find_in_set(1,cscart_payments.usergroup_ids))"
        },
        "table": {
          "table_name": "cscart_payment_descriptions",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["payment_id", "lang_code"],
          "ref": ["noframes_angrybeaver.cscart_payments.payment_id", "const"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "trigcond(cscart_payment_descriptions.lang_code = 'ru')"
        },
        "table": {
          "table_name": "cscart_payment_processors",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["processor_id"],
          "ref": ["noframes_angrybeaver.cscart_payments.processor_id"],
          "rows": 1,
          "filtered": 100
        },
        "table": {
          "table_name": "cscart_addons",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "98",
          "used_key_parts": ["addon"],
          "ref": ["noframes_angrybeaver.cscart_payment_processors.addon"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "trigcond(trigcond(cscart_payment_processors.addon is not null))"
        },
        "block-nl-join": {
          "table": {
            "table_name": "storefronts_payments",
            "access_type": "index",
            "key": "PRIMARY",
            "key_length": "8",
            "used_key_parts": ["storefront_id", "payment_id"],
            "rows": 17,
            "filtered": 100,
            "using_index": true
          },
          "buffer_type": "flat",
          "buffer_size": "75Kb",
          "join_type": "BNL",
          "attached_condition": "trigcond(storefronts_payments.storefront_id = 1 or storefronts_payments.storefront_id is null) and trigcond(storefronts_payments.payment_id = cscart_payments.payment_id)"
        }
      }
    }
  }
}