SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '686323e6400da0dc848d5732164309ae5834dfcf0bdbd7b19d4b28f249e8d985' 
  AND token = 'H4Az0Td1igABYU4CmZbofhaielPD0DDdwrfBoab1FqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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