SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c3d685f5cbd150201185a27f51b88bb8eed5aa2cedf39bd950613da4fab1dd79' 
  AND token = 'HPJmnxWjA7eNv+VLwJP4oyOpAxZEupxZ3+7EEfxwE4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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