SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f5fa68b338962bb03cffbd1672d654b733eb598d5d1dfc8011404517d067589' 
  AND token = 'IwWe/auIpjUn4lC1nOXFCKQFDBIIwt4riTY3QxlqThs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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