SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29ea31004a482f40e120868bc7e354360ed1f6632e27741eb7e09eaa6993963d' 
  AND token = 'QiaVjB57GzlK4nbjJ8DMszuLGUqV11Q1uzoJcrj76pY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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