SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96c2701a36bd304fdf04b0d2855610891f52f278c9ca73086ac001548a531c10' 
  AND token = '0IYN8KtytXd+GpLKUFCzWE1XgEd9qaopgZjf8BqgUiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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