SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a134defb8785efb59ba0c00b5e9dd71f39d7918153e375afd458f7fc13c4476' 
  AND token = 'xk8cHgI5gAYESK+WApzO9wypd7EuIjmLeJYXaMoDtjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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