SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3573b371f00dd24b36495b91578d884151c9f58775771324bcae311d405c4fdf' 
  AND token = 'cVOuBVhuZ6nR0MkwrhlHGpqTWGhrva7b3xkjaEwMF4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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