SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '456352ac89ad1734f244126de10756b99f3d2ec43f9455bef6921bc289cb041f' 
  AND token = '9Iupw4qzZeA1M+0Pp7S9Pbq4UJFF9LJroygZZplvz10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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