SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f517c1c235ce15421bfe919b6f1304c7a897de5dfe9f06f065cfb0cf33c7263f' 
  AND token = 'z8JB8abZnI6nZNLooXV7r+hqNTY/ZIdhOvBJEJ+j7jw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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