SELECT 
  COUNT(*) 
FROM 
  netting_promotions 
  LEFT JOIN netting_promotion_descriptions ON netting_promotion_descriptions.promotion_id = netting_promotions.promotion_id 
  AND netting_promotion_descriptions.lang_code = 'es' 
  LEFT JOIN netting_storefronts_promotions AS storefronts_promotions ON storefronts_promotions.promotion_id = netting_promotions.promotion_id 
  LEFT JOIN netting_promotion_images ON netting_promotion_images.promotion_id = netting_promotions.promotion_id 
  AND netting_promotion_images.lang_code = 'es' 
WHERE 
  1 
  AND status IN ('A') 
  AND (
    storefronts_promotions.storefront_id = 1 
    OR storefronts_promotions.storefront_id IS NULL
  ) 
  AND netting_promotions.promotion_id NOT IN (25, 26, 27) 
  AND 1

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "storefronts_promotions",
          "access_type": "system",
          "possible_keys": ["PRIMARY", "idx_storefront_id"],
          "rows": 0,
          "filtered": 0,
          "const_row_not_found": true
        }
      },
      {
        "table": {
          "table_name": "netting_promotions",
          "access_type": "ALL",
          "possible_keys": ["PRIMARY"],
          "rows": 6,
          "filtered": 100,
          "attached_condition": "netting_promotions.`status` = 'A' and netting_promotions.promotion_id not in (25,26,27)"
        }
      }
    ]
  }
}

Result

COUNT(*)
2