SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '500e984ac5e9e3c355e41d238a579fbd64119128fa1f8df7f0c4369bd8f248cb' 
  AND token = 'TnvhUXhVzxPZZXAlbv+S+hFbCsVA1vcHXW2lnXejy9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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