SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf21aa99aa5482d4553b283f3ab53b43786655b6b902db82db6eef65edfca0c1' 
  AND token = 'Kh8FHojtvSR1yVxI6FGj5QnA4ph/aVQ9e3kn3hhel9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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