SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9a6581d9edeb96edac54a497aad276f03e40220c305f660284ed569bfba845b' 
  AND token = 'RGgbkc1On9rUdD0DqV4dprwe4d1G8T/+B7yRAH9nXbA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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