SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45e15bbe865f530f481626c1282998f1dbe69a18396aecb3fd1964646473539b' 
  AND token = 'VjivyJSDOE0KSXl7b1/Gox+ApSlJpH2PpepuHOh1qWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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