SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92ec72a2b16f345340ef4f6ef2b87e85d268ede7732fb32a8cd3de029007aa5a' 
  AND token = '/yiT9GnYQlI3/n0Q9Xiw+dKV3bvRVJtqQxeu6vjC1pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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