SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9cdf8abe3a5aebe5729fd2a36edb8011fce2907246f724fe044eb37a8417c78' 
  AND token = '6ZObpsyYdOW18+iZGGtWNiKYIWWEbDgPFQP1OYh0K3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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