SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6d1b28a7eeb42ce6219439a63c75bb96739987460cd2952e100ccd666d0f946' 
  AND token = 'Ew8ZCDagB5cRzsUMKbb2eIwxJsECu+/rq0Rsl7vei0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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