SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '127f41911059efecc0e3c7d06029f047649dc52cfd5dc9559532f5726e1099df' 
  AND token = 'JPtyAqKeD4HH0CMPgjhVRIoKOWPZ+bUaoY41GpEYmz0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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