SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5b65933387936242b6a065ee6dbca23bafa102b113c4749c36cbc5b63610995' 
  AND token = 'xsmXCwznrEsB9dSmkjolrKrAY+9P3xmqYH2hY0x0WRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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