SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cf1959655707b3b89e4abe12665c39f3a3938fe8e49e161a99ad9c9c8abb696' 
  AND token = 'rZIeymDhPmB768KyL0GQenaoudCkq4V6qDsvOoTpTZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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