SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57dbcb732bce6480d2a6a887e90de708048ce4b7a31ca8470c6e4f8635d23e76' 
  AND token = 'K+DBdsGgJ3Fg+WgRdj6YlFEERuZQ3i19nlYazZzVxKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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