SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '402e5540c520a7834b7982821e4060f787f5c9f5d1315db19a6615acd0d2b227' 
  AND token = 'T3PTZQHTfQ/4ValnHqzVh8EUAjzHLBtY0iaGtN8KmKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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