SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c16a99885cfb2b09dd2877fe9e38893364bfcdc8a69287fd6792533ad695d73f' 
  AND token = 'WXIqWZrPXfRkBmwjds4YSnd/FFE/JDgj4cWUY3lqqrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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