SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc49f7f9cc63f8fda65822db71a3f68134daac482ddf498354d9dea3babc7f6e' 
  AND token = 'fa5XBAcDgnZ0U+QIux9MbLK9j7X2vzMW6fBxUMIxQr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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