SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cd91c3db4268d53883a8b4086569cb97275f13386a22573e6e54a024b6cce28' 
  AND token = 'mrDAEBGMMb/QpHGOwsbd3q92h0IkfYjktYY6xWWeGGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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