SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b5dc597e974f8bb64ac33e8a35eeadc5b4320490afeb60bf18dc69d88697d3e4' 
  AND token = 'fUmdbwJiQgDfGAYnHgRLTarW0z5pLuQ38KXXwlXREx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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