SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b89afbb706d9d8d155d39fc4a192ae5c85ab9a7120924016a3087a73d1eaad9' 
  AND token = 'JGug9PfWGXVa9CRpE+bLuFnHzELQUBvw/vGAgX/NfiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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