SELECT 
  entry_page 
FROM 
  cscart_companies 
WHERE 
  company_id = 1 
  AND redirect_customer != 'Y'

Query time 0.00004

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_companies",
      "access_type": "system",
      "possible_keys": ["PRIMARY"],
      "rows": 1,
      "filtered": 100
    }
  }
}