SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f31f6bde9a00b8f241f7c5b13f053e66139db1081f67cfaa058d0f495481b11b' 
  AND token = 'slR7YCCbncXt9Xbj/Ekh74YGOHecuywDlS5pzlLq284=' 
  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"
    }
  }
}