SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba6f4f379f513df699a2274f40028e332d63d370e18f27f0d67c85706bd94448' 
  AND token = '168YSuu+NdTvTRROG4gNeyOs8phxQ9HW0AoCZiB/XVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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