SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3957d25483a9345bafabde19612cb33b751603a91dacfea2f6d530e4d86169ff' 
  AND token = '0ZwbgZrYC4/WWOLVAJ4MST14Hxlw9PH9wlEyfZhgTG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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