SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'daab55f696a30fdeebc8be28d6e418c0cf1bfcbb61985a6b42e6b6adf998fe99' 
  AND token = 'ar5zKvgN5vuIGQoXA9areh3UGRkSvhUlC/P1KMH+Bcc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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