SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62fe0235fdb18922210945cbd4f894d96d703ec0c7e5c081f278c810cc3c49dd' 
  AND token = 'P0lk+mx4/5ZzPfJlSAULKeCCfkiSkFqXVyMvYYOl7jI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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