SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a816d0d76a63f98885019d371cfcc66816428a8b2f83dd014e246ce521115f9' 
  AND token = '3Z4p2VSh34klzyWQFgffrQNYdyJXF9ddLvuUJbLyxRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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