SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4140746e62062ba6a4267b7ebdcff7486a1b0462ecdc9b86600b7dbbbf029fd0' 
  AND token = 'NUOg/mQVtrIbyApYAeK1B7BKzF5bO7uW/oHpxnkClXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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