SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '757d79e978447ad4fc4081e4c9b975a91191df37566223d3c51910db91e957ea' 
  AND token = '1/53QTVF+YxP0nq0Ac2UQD8WPkUfzdOzVEaRd/InDTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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