SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c086b46c888a7fe758d616aa446fece5a2189c8fad541b2af4660a017d6eb62' 
  AND token = 'ZSL+OSQLShrttNyDw0FT6zWG5MhBnGvOkG23O+i5iKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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