SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1854, 1853, 1849, 1848, 1847, 1846, 1845, 
    1844, 1840, 1843, 1841, 1842
  )

Query time 0.00085

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 (1854,1853,1849,1848,1847,1846,1845,1844,1840,1843,1841,1842)"
    }
  }
}