SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '356abeb0d2918509b9e1d94600b656b13adefc3e353f490e566ec54351bc7a2f' 
  AND token = '0GWvZNQKr7xEpXUJsQmxJmWSLOppS6A/BYB37uvwNiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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