SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cd944a27621131541868e94b93805969d665afddb576d247cfb1047cf579aae' 
  AND token = 'b0lqXnq6BIYJZHT7q6a++nSfHQN7NUAhBzNHFXM/HuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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