SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'deff917940f6641bff36a232e443253c1d9bdf36d99107f5bb096d6e6e99a8b8' 
  AND token = 'UEf5FfKZqA/WjAg9RSYwMNbztjlK2nIdWs5uiWlizqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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