SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71ece965871f9a4e9e999d576c41885d2f589d933bcbd411d6b6991e0ae0613a' 
  AND token = 'RpN3CRT58pwJ/VcMHYnXFnxJrpIfnZPaqK7QFCEhgnw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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