SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29306422bdce013bff1f49a7d50d26408b1210c36a7682d5fabb2691c4c4ae8d' 
  AND token = 'UbiYumy6D7KvbxDYTY8ch5JIjrxEdvxvdAuBIE14oac=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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