SELECT 
  cscart_products.*, 
  cscart_products.ebay_status, 
  cscart_products.ebay_template_id 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (
    20077, 20078, 20079, 20080, 20081, 20082, 
    20083, 20084, 20085, 20086, 20087, 
    20088, 20089, 20090, 20091, 20092
  )

Query time 0.00036

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 (20077,20078,20079,20080,20081,20082,20083,20084,20085,20086,20087,20088,20089,20090,20091,20092)"
    }
  }
}