SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57e3b8eeddc04c261fd190f11f96f377b00dfa4c0becddc43d0db397f87ac545' 
  AND token = '2T7FYEFO7pZ5EniXWOpbyLe05mKpdQDw9qxs8bz0a7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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