SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37455d45a3df904508890b7bb1d2107ea4dce91930d3e5db183bc8720f3804a4' 
  AND token = 'wrR1PbeYJfv/kUhTa4dBegNqfuC041UqCW5WEgPUwiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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