SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8694f9287d426e1f76ed9536ff444da34a5dbd83ce5a732f011bda5f0d8f4561' 
  AND token = 'm7GjDzwpQwM5NBbOJEWVBfT/SPal9jBSD6gibggu1iM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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