SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '832c8bb2aa08d37f84130863d98e050c181f16cb0dc0d4c6309e03b20b914c60' 
  AND token = 'lXVFSRMa6WoaCVpSkwWvUfYcuOlgBGgB3LeQT2Q1MCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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