SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f674438b7506a9593d8381cf8c4944a12edaf88c6a8671ef53702ccd2bd7a93a' 
  AND token = 'beP3xI79n6apbY3XuVEY4v/1lFdVWNXsf8e9tkZ5jEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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