SELECT 
  1 
FROM 
  q_lock_keys 
WHERE 
  key_id = '620b6b271efabe2379599dea1420cc2f48b6987f35e6d5b1713f5d7a259b2f7e' 
  AND token = 'RFW+SkJBxWM4dujgsbGHVya14qTg+LR/bdaqCjvMi5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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