SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3edf6dfa4e3c3221cafa449a0f4283f9039452d5d4bf685db462872f24551296' 
  AND token = 'Wz6rKCkSW7Rv+qGBSgtVIWm/IBu7EOJ5VTJrI0oC3do=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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