SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7104d24d4ba2ea2a4c97fbc8558f45d7cdcf555efddbbdd0d349a57a7a274f78' 
  AND token = 'biPs0xbu7L03p1LmOwTip1vLwOmeLtbqHtzjGRMVwqc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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