SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8c21a94361174e32c5cc3ec76920ebe95ce7dd54a67304627fb2eaed14b068e' 
  AND token = 'qBJveu1WCISOdKJIThSapGEwBwHzHF0vxBA2MYefdSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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