SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '340cb0db43f94169f280a79581ad7536d0bbc62e8cd78605d998429f91e73091' 
  AND token = 'suxHd+ZfA9B/Sb63wdPjKfwLtRmTTTzU07nyITX+ET0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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