SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6120c7f21d9bd0daf186932cc8e2ea19618033b5f140c49d565d60658eeea969' 
  AND token = 'jBcOu7VIGmmULFMCeyQA+hyMFU2QxKqAm1FWjZFcSuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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