SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4c670456bd8deb85384ff97cd502e0dfc11ba4443f469f3a725997aaf36e8e9' 
  AND token = 'qXxEeu1vLuDvpjP4z8jlXs6jqUqKZxDhV52WduBWoPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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