SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b32025a70e5f3eec4d1f03eba5c9f2d75b09bec55387e5066d402c4be188d95' 
  AND token = 'CT6ApJ6ZcrFQAdYOv4NSFd1f36Al3AeSPUq5Xaxk1yI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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