SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bbaad8a18b3dc48b0fd58551955a55f1b5a207cfa292a6212dca405963e622b' 
  AND token = 'eYTyGy7blQkEdtlce+QqSX5xmPxtFEbbtXGfKZ87K+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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