SELECT 
  product_id 
FROM 
  cscart_product_popularity 
WHERE 
  product_id IN (
    15700, 15699, 15698, 15697, 15696, 15695, 
    15694
  )

Query time 0.00100

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": 7,
          "filtered": 100,
          "attached_condition": "cscart_product_popularity.product_id in (15700,15699,15698,15697,15696,15695,15694)",
          "using_index": true
        }
      }
    ]
  }
}