SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66acd3c4045c97dabdcfbb97623f970d29e03517ab7c4450b7ba931320606fd7' 
  AND token = 'qQjQG0pshjl1KzHxdLQzqpxrzoXjEOqvTZABJpzQ/Y8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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