SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aeda6ffd8992f96c0c91642b67fe4827df8de2ab72b7a14fb7d95e2cc42cdb51' 
  AND token = 'PaIBwydd0AKTfqjFE2bZ/DxoZcP/xqM9l6lD5SMIPqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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