SELECT 
  id 
FROM 
  cscart_sg_product_views_log 
WHERE 
  session_id = '' 
  AND product_id = 488447 
  AND viewed_at >= 1791599486 
LIMIT 
  1

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.00345856,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_sg_product_views_log",
          "access_type": "ref",
          "possible_keys": ["idx_product_company", "idx_session_product"],
          "key": "idx_session_product",
          "key_length": "197",
          "used_key_parts": ["session_id", "product_id"],
          "ref": ["const", "const"],
          "loops": 1,
          "rows": 1,
          "cost": 0.00345856,
          "filtered": 100,
          "index_condition": "cscart_sg_product_views_log.session_id = ''",
          "attached_condition": "cscart_sg_product_views_log.viewed_at >= 1791599486"
        }
      }
    ]
  }
}