SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6895fb43f12547b79370486df0b0f1a9cc9baa64a7048dafe4dfd649cb1ebee9' 
  AND token = 'RcscWAHL/BzktdXywrcF/6dg8/evcMXVfMfvfiBlBgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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