SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab259ed607ffdda7449ab46543501726c86615d1c5da52f59008e2025c775f8f' 
  AND token = 'YuNgaIMpVqEYnDE63R5psWKUp9KKXdcZsFJLmqHywuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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