SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '280a9a3f964ecad6a7cafe40b9ae485678e350d372afabfb1048c0173277914f' 
  AND token = 'aFwwPmQ7x8MejoK/Nnhbe6QDXMMcHKl9zNUTyetaHvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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