SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ac4cc2466ffe804ddf7b33117cf30c83a1651f713b9e3b5438642622897fe4f' 
  AND token = 'Qp6g8NnT/k6RRSjCKPvvryKbtFYuXKcJ6YdG+UZqGpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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