SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d121bd14d6327ca3ec2659403567f69f0c91eed8575e94f538cd5eda39b24d3' 
  AND token = '9xifulRNP7yKAGRwimp2nPZZD/HcZJHQ/qy+v6Oga0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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