SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35e533cb71b41ebc0a9bab19fa772f380e7fa628ecbe0a2cb0fcb55cf5f4143b' 
  AND token = 'k0PK8n++qDwIcgpl8uESfzkmnTDbzfbd07PHW4Q6vWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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