SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '21b89a6148004342d5490963f80a04b4eb48834d5af6bf5bc4bb626f25e8574f' 
  AND token = 'IpDptGtbngQVYolsGCf8NcjvDvvKaSMOoikWncOHTPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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