SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '993314657f293a0733ad6ddd396f61a8647bb4d40f09f79a653cb50b725d6cb9' 
  AND token = 'sIsfi8l1AKLHgrLj3uzE+D9KCbhkxRsqgS9CaaJwlW0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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