SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c143cd4e33964e082c3906bcadf39554a5c21fe42798fef5043c8a9409bbee45' 
  AND token = 'PlB2xW8rX/Zd5zNWPhVL3KX6Hth59ZJrNyH29t4cLus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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