SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e64684171d26e0691ec828368dd1104227791ff25bcee28be6af0ad43f37873' 
  AND token = 'WBdawwMSeURrNfN9cExwUql7txyqIBSKoEQXs8u3yXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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