SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '762ff6c3777ecf39fda80ac014924333429b49cae2e255c891655251e04392ac' 
  AND token = 'DAkzCljoLyqunKEIwgE++lJe2/fPLGeeulQGsfq7as4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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