SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7afaf0a7cab664508398311376bc380d7308980c63505511308f4275372e273' 
  AND token = 'I/EsaUyMazcf3XkuF6tR+vRr3l12iiQRIQ3BlZnYyVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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