SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '836115668781063b7ffb075b2059c1bac026a133b7ca1c3fc2f25031e90fd540' 
  AND token = 'WqYnIigmPqiV7wLybiTdE3/5/N4R+TpKIyrKaexhRzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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