SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6a1efd05be44f899e255f7e3fdfe330dd48d51fdb5f318537174e8a3bfff0ff' 
  AND token = 'hK7vKTm8QnwikPsT2X0qUgIcYnCF8kX7KbNUerlb1Ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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