SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9142fd77eba5b4abbddd174968e3982bca151f2eb0a9c805d904cd27ed882923' 
  AND token = 'f40lMmdq37KrUAHXV5VvobiB5+jmDllz+FByEuKTDYE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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