SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99eb1aa421d38f3b3a6ff764f265b19dd07323d40732ae8aa5c0a484a81064ad' 
  AND token = 'ohJBnNq8J25nuis3TkE2FocozAY8YtYW2oknx+QgBc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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