SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0ae3f4155dc059063cc6abca8b2f2beae4815a4eb62a8743e503879ce5dc88d' 
  AND token = 'HOEbMVbmZJ0Iho6BKTFYnC0lPHoZZIzII7sE/CrtrwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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