SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '483c61cdccd7168f932798aab57185b2ed42ad1f972f68190cb68ae2bb3e94b2' 
  AND token = 'xj2i4ar5kAIp8Ql246RTwi7KlCjSsuNPbKcJLq+rdOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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