SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6200f29ca2e920300615a43d24faaeebf2360a1112c3645563994324c1c47f75' 
  AND token = 'v+hPk8AzJy7WsgDJ/iohnlBm53A5AFwlYmIp69SH0oc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}