SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7024d604904c2dc98ec138b41c60349f9c2db97dc27831debcea3755d61e354' 
  AND token = 'k4kYFHNdwapVZaYF5BTuIjC/sXipkXP/UrIbAEjjuP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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