SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed04ca3a006e184072cc0c9cedd1fade281b0fa7c29a701b88455543366ded8f' 
  AND token = '8L/n2nVCQI/hq3aa+2uVlztD1KB6HUJrJCS1KfgCqmw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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