SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35efa3db7eebd5122eb023706b24489413e2b1842d72602bb011f625952bd668' 
  AND token = 'XSO0fNJ8y7QvpyhTUAOTkUdOGWvPu4qsnW9WrpRjRI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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