SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cbee7e213dffb832a11f2c88ee34475998cecdda6b9843b56024dcee836edf0' 
  AND token = 'ZBo4zRRwlp88kH5shHKZNpWqj72IMsgSgWto2cC2lo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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