SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acfef8a5f699c0fb140a6f297cb105e540148794bff5892a992764589f2ebf8f' 
  AND token = '1gspV3uCDP+5WsSmGCgVPToTNc0qT5dxgAdJjgzW2LM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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