SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34a8e8291abbbffad12b491020d7bc6cab5a692e95783d83f81eb81f330845e5' 
  AND token = 'GgvDPXdBqHQ839YKmESMcpPQHW6k3sz5jtUwZrvLHdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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