SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a76e9c3547a2bc1b08c92eae0cbfe313e8e18962d9c450be64df798ac212b9e' 
  AND token = 'g0VMAkAzbPOBDvMD6IFdZDAamt1TzN1MDzzxmesKv+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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