SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb1dc7d54e7c84271b08167bef7eac3c431a4a232a57b7b073d85baa7997f79b' 
  AND token = 'JkcETKpSYt7Xti58/QXO3qzqm8SuH3PylV9lMzrIBZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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