SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a41f383e31e1cdc2398aae80b4fdd005d576eebabdf7f2458fea432a43709ca' 
  AND token = '+HJtJhYL+CJEwIjV7qv/UdvsuC9jJ0gJvjhj59VqOgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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