SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '369b34db0bfbdedd196c56ba8788374360a61a7854ae4e5a6896495a36887e8d' 
  AND token = 'a9BxLoqWk4KyiP2JvIMhFmoXarOvt01ykz052VgkZaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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