SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98ab94bccf745c83eb9fa644c53e5f919e6c21a80ceefd3f0873761434e3b4d2' 
  AND token = 'ySP8ZSOvGC6rFA5WCzKdaxhb2LKs0jyMVK/vNJIosw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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