SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac8f85ead1c0bf91db25af3bb9d2419a436842befa4fe7d9e385594d5e595ec7' 
  AND token = 'Xc4QXNsome1LFZnGEMaul6fOGN3UUBI6R5gFu366c54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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