SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8558201eed112b163baee5e34dbd770f4aad00a2bf85f0a43622c475cb7565cb' 
  AND token = '+UeQIhk85RvOzjlxtHDGl8nUUb1In+bMY5NHluemqHQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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