SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b6efbe3040ab87a2dbeaf85af4546b5a3b9eac8039675c943f1768630855eaf' 
  AND token = 'VW65vbjp3hmVVBz7qOWiNOruWl31QBaKl7IGKk77aNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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