SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c654708d50b8cefadde15bbfec18f280c2ee1122133d3ca1cc7a407c740a78bf' 
  AND token = 'vCZgGj5fV0Xwjk0L5uab77fANiZ6ggXgGP+1qSK9Eto=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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