SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3aa279af1c54eaaab56b948e676ca39f07f93b980e2421fd3631bcde9aead6f' 
  AND token = 'LmFyBKlyWGr8rLmcwCeQIDnrd2psBgUV8+AS+5iPWp0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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