SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2adf3c56b07ddd6cbf778edc6c6c9fab90790406fe70dfd89365e35203d1a57' 
  AND token = 'DMNQktLj+7lQeNdwc+igUcU/vhDU4I7TZ2GiowVHlHo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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