SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cfabf63405dacaac3668ffee1fc2a9c57aea9d94665bd4723e0c718ed375154' 
  AND token = 'maQrMJYkH4NO2iZgkGJpfFvgZeSbPdOZ0QyS4Mq0EvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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