SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd18f61c376ad041ac034b3bbca5b343af606f7a410652c48466d702f592309a0' 
  AND token = 'znaj4YsVMWHX9S+AGhufaKVcjLyG1w3gQppcXQIqgc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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