SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa315d1509d4d6382826f87f27064dd9cbf53a14acd828bfce8bb6afab9b1870' 
  AND token = 'OFGgnqLGZ9ov8pQeQ7lhn+eJXT+Y9T9iCkEfzzS1PhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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