SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5967685c9f2f35168f1a78fcb8100a1403a31f04fdbe53bd01f0995f1fb35298' 
  AND token = 'VhJAPfbD+RqC9w9yDfiZ/3OKGORaUxwBz9FRlZiYAuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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