SELECT 
  value 
FROM 
  cscart_cp_sr_product_allows 
WHERE 
  product_id = 375 
  AND object_type = 'c' 
  AND company_id = 1

Query time 0.00025

JSON explain

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