SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    1584, 1585, 1868, 1579, 1956, 1495, 1739, 
    1740, 1912, 1913, 1650, 56
  )

Query time 0.00092

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 (1584,1585,1868,1579,1956,1495,1739,1740,1912,1913,1650,56)"
    }
  }
}