SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '798b84192f7f23d7a37b65fe1cffafce7a0448a3cbbf1e2efc3a092ee2f85a25' 
  AND token = 'Ib0zfBjjFG7sprkZzor+OyJNfAdl15blTUZmUYREd9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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