SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8eb705e37900a887017161e589d6dc320ec2ace7c51714ceebff464a3b852c55' 
  AND token = 'BwSop6JPLVlg4KxKhIPqS0lvZkh9gySOm/Zu9iqgCSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}