SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f409884e8742a79f01c1869c855e94489d2598d7f509497411eac02882a5f510' 
  AND token = '9Rd9V6XzOhhRATq0ig2clQW95AHAjkIEspqgZAyZjFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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