SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d20ec9dc5b7e58dc5471a7f74a795f0596d946c5cc3dada301503853b227861' 
  AND token = 'e/xrY9zUDFYjf9kjdqBeNUwGbj+jzIMi/tYE2baXyf4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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