SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ab1daaeb321825ff2e13872a57e7d7cf971b34ea6ee3395eb6dc87caddca03f' 
  AND token = 'JYQhJBjLxI03eXt22t1krRuDwmcp8wnsMNsvnDkzQAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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