SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ce6fe3bc174712fbccf278201bea676441645384413694abde3dc2ca20f592db' 
  AND token = 'WIxDQdLTPmWHeCLqnnqZBHApzuMrUZsZff3fBX/pmFU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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