SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf4252cef52ed604e511005df776efe461141781c93f33479bcf18878138aaf1' 
  AND token = 'HyIcqk+3Fr4A/qyS/fgx9Ygc/+ojU5Z0aZICkGmvSwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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