SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cdc3c8aa39bc426f0aca031598922bc3bfe1df465138bad1ee8a32956562c61' 
  AND token = '1VBJY/ibiKVHsDvs5o1S26ZVIHz4yioYXNtiB+xQ4/Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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