SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e40f17ec353b18177922edea67d8d7656cdc1b62021cd594d2d3497e5623e58e' 
  AND token = 'lT9RxitwcAyzJyYnBvW5wPpuZr7mZHQtxiKyXxRo9Cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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