SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dbe7c2f7f35291457a5d7826352f2dfec265c67e4850df936820962b2f1780f' 
  AND token = 'THljaVgEeVglYfrEl4ICQAmAqw7Rcq9FVvhHOPOoDMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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