SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e43488137593ef2006a92950d3bd908c293ddd3bf7e2ba1fced7a3fd0fb30c00' 
  AND token = 'WxwDUeesQDmXjW2vejYBx4pBQerUDKeVgqDEAnC7eN0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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