SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dfc75f78953b0d0522c258f2651e6443727b26be2171a8ea47a60c57992cf1f' 
  AND token = 'v9oOFbWIwKyce9N80BmQZXlZnIqBdI2jGFYcpCWdFco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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