SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5eee35ac1de5c0d9b35aed419bca6fbf268650faf17d1b22df3cadfea0413a60' 
  AND token = '/fhhOdMbyqEmgdETKeB4oMmdNlsPAO5tsIes0NcrT1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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