SELECT 
  * 
FROM 
  cscart_cp_sr_product_allows 
WHERE 
  product_id = 78 
  AND company_id = 1

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}