SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c0da260c051729516f5cc9028a31ff77517cf36976df97f21ebb09af3f138b7' 
  AND token = 'OJPBpVFhSLdZC9LI8YaOPd4jgn5SJyOT/KFPnIyJeoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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