SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c7db32ed43b9d5aa3d37cbbad7cfc71a3428f48d8aed80661a9584fe18d7551' 
  AND token = 'FVeHK48/tvm3PQlHbJ4M1AGBlusPgveLnrnbA9w+wIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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