SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7877d622ee6d67daa728ca4cd567abc5ca175cf227ca2b824f4e61e1ab363e06' 
  AND token = 'LQYbMEGelK6wqzsIoaW/4YnqQeuiilDJMNE7lfcM7Iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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