SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6efdbc8961b6948048e20c63f156eeddb07249f93bc1f3b74fedb5b252e99779' 
  AND token = '63RDrjsdMFJQXAgtF6zb8TpnwPpFrIZKfDFuhqwaRCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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