SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db22856c24624932e33ef358da964d2797dcbe656ddab74cc94491252545bd72' 
  AND token = 'xNvKKrmSaIUoh1EzfY6I324u5RxqUmidyH1Diua/ZyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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