SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fb6192e4a02a900cd0b98c60dad5a1a9d2891cb285ee6d6865f139a331c155e' 
  AND token = 'Lv1pQgjjGy8JoaXRUdtvEoM1e/TZKiEhxuBZlwHTQu0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}