SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc785fb290aa6474097a3c7a1570f7b3d88a6cc3ad31ab8dcf119922d1ca7a86' 
  AND token = 'oodUGQT+clYi+0h6dJ/Hg4oQywOzF0UOyuhaR1Lm+d8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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