SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c46ee6e3017f22e69a4851bce15d0883b9db5c4bac0556e13922a3ecff00634f' 
  AND token = 'AsY5gyLoOaN5gJFFsneZDd6OeEuRmPOg/z9rwIpHdbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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