SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    29939, 29941, 30003, 29949, 29938, 29948, 
    29960, 28437, 29945, 30001, 29942, 
    28434, 29940
  )

Query time 0.00122

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_products",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "rows": 13,
          "filtered": 100,
          "index_condition": "cscart_products.product_id in (29939,29941,30003,29949,29938,29948,29960,28437,29945,30001,29942,28434,29940)"
        }
      }
    ]
  }
}