SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eefa77054faea7de422443f06edc7d7f7fefff1596c5ba6b68dd7575b91042c6' 
  AND token = 'RiWJ7hGWNh9ytv1cqF2uSvYRFXaIM6dSumHXvifoMpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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