SELECT 
  product_id 
FROM 
  cscart_product_popularity 
WHERE 
  product_id IN (
    32138, 32139, 32140, 32141, 32142, 32143, 
    32144, 32145, 32146
  )

Query time 0.00459

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_popularity",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "total"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "rows": 9,
          "filtered": 100,
          "attached_condition": "cscart_product_popularity.product_id in (32138,32139,32140,32141,32142,32143,32144,32145,32146)",
          "using_index": true
        }
      }
    ]
  }
}