SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    13091, 12638, 12639, 15800, 12640, 12647, 
    12588, 12641, 12642, 12648, 12643, 
    12649, 12644, 12650, 12645, 12651
  )

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_products",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 16,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (13091,12638,12639,15800,12640,12647,12588,12641,12642,12648,12643,12649,12644,12650,12645,12651)"
    }
  }
}