SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '115cc1fec25c54b537f4518a973064bc1d45c232d22ebd417a474779617cba50' 
  AND token = 'sYTzliPXW9qnSIU3vFHKsvF1+JT5qnFUNRAeYr3IQm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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