SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f6d9337d9719bbbb7d8c0faa5221bb6937ebf7db03e9f63646df2b8f62018f7' 
  AND token = '9zxAvw5Cgochvae0QKIaKIsAhgeMtNn/9BGj5VmRYho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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