SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f3ba2b8453fd050d93fcbe014ad2e53d14127d035c584d51c0f5da66183ab68' 
  AND token = 'VAlLzPRnY0GDRCeotb6QGKclAUhWGg715JaR+h1MtlE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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