SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16c5e6c760389b287b88f7f3d027a6085362db1b9d2e4bcdc76a570e943e1462' 
  AND token = 'EbYBxo5tr1QgCbpfxCm/hqqiVFXZRmNF+golQn/xPGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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