SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4420090768b28c7f36ecd19b3b1a48aa1b02fa78d39a90fef862c4e37b90b36a' 
  AND token = 'yC9lJs28SghJ6txANCQA5smlghQsB/m+zpHKA7PIAWA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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