SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcf50e34a74ed1f9a70c5a9458d67921f8c3c00b898571bd7b258cd666325057' 
  AND token = 'HTMKqsuheKZeLUKt8pTeZr1OIZ+yXm/wK4+jfFhopjU=' 
  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"
    }
  }
}