SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd81e211a166c195315abf9533bc7b0b8d3a4b94fb226f6972ccb76f6737730aa' 
  AND token = 'rxNsrKVBzvXN8PbWfNROkNwPzsZirP+9nRvVlSeqPEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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