SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc8cad2ea373b9821e9017b5696cfe1c2fa0f64a5cda54a36ddcc51de9baf7c3' 
  AND token = 'fpqv2lELEH8tKZ9kwyskDg2SyEK8hOsk2cGvKgmuvKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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