SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81dd68d419cb4cf692df4d64693231c58f2e7dfdbccd25f0c7ec3487c032e0b4' 
  AND token = 'vpqZPb5RqLNocvzuHYluMJkHwNYG8DMnsOYWB/hz4QM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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