SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49dcc46266e43ff219ce87d6deedb03084f2942b24e6a093091a3226aaef8783' 
  AND token = 'LS0PTAm08uBrocuXP7QSOiP2iNusd64gCju8BOvGpHI=' 
  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"
    }
  }
}