SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c953cac582af320e94113b9c637265e885e86b70a9c91092f5ad36edf34b4600' 
  AND token = 'CeLF8KtjRAv5zt4tmrL7d6V8+Vof4nHKR8vQCK9DAuc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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