SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03cccaf5ba060d494de4d3914799682f725dda338639e5462671f6dfa97a38b9' 
  AND token = 'xKK/rFSDGOf7WANYP1ZSK5C70wOjCrMUhszbhOmp2SA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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