SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1865, 1850, 1864, 1863, 1862, 1861, 1860, 
    1859, 1858, 1857, 1856, 1855
  )

Query time 0.00077

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": 12,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (1865,1850,1864,1863,1862,1861,1860,1859,1858,1857,1856,1855)"
    }
  }
}