SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61ff44da0de6cb48285d7fa22b537d9862a9147a0316d034e272893b5ce0c72b' 
  AND token = '/OxvDf7hzhxJKVsLjsXXaHODhEDLUayHAeZRR3IIT5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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