SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5776c73115e96b22579c32fb8d9cafb0cc1756cb89d2d44d8a1b4e8ec7c64a36' 
  AND token = 'IlwCDMro7JtE6kaklGNjcff6WcUb8vXBsYXgihMuSqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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