SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be559d8a42cabd8c71889880569bb5fdae79f78aab5448e34ac1af164962de96' 
  AND token = 'Evm9aX/Ew4GNUhxbhdGcuWbZK2B5feS9oXlUNQId+qs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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