SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbd1b66f1fab655c325459964219cf87ac41ac92d33224d14abee40b5a0cfd63' 
  AND token = 'Zm3NJTeNOH3mGTVtJuabKHPcJFwVihJprAgZ6Wo2+Ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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