SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2bf66dc33213146c677748f2ee0108ca4b2e36213d181e76df93644f77d6543' 
  AND token = 'H3NGUm8dimwPcWlx3ERZGiF7YfYixxuaQvW80l9Pdv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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