SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c785ea9239d0ee2f88ae3012238eab13f62cbb02dd8fd7aa51ee76c462bf4b2d' 
  AND token = 'j4En4quhiKBvHTIvstfz6+qpMFr6dhmZnCBCvVKNsps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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