SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae9bb94bc00194336a064617bbe64ca253fc66417d2018f5b4510342d8241393' 
  AND token = 'JtImLAfp5pMlRtLZqIMTZlb81OuGhy3e7XzjVnvdq4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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