SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bf8d25fb1ba5fcefdec5b1303a25f7c25f5387bc631fbab7d2274252b737a9d' 
  AND token = 'ANwBHBDqEdI7cM/dY5uE5EAXsAlmiykEFmy9+mWJliM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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