SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '195923b6deed8af78b7de049e66e13328417e409bdebfdac544163eb38fa774b' 
  AND token = 'oVA+mhssPJhJ3EDWVt//oLU4PiMrV9FhnC4obvGpDzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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