SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87d2ebd67d08ec90c578b52643fd8c7f8a4fe297c62c5791e9ac54e97328dce3' 
  AND token = '20q1b5nJahesA8Qmy0HLS/gFa1oAWT0BoPgK4ZGjrS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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