SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e91ec1e0588be4ad8ad25b5623b7c964735bec4b8deceffba4f74457b25d37a1' 
  AND token = 'P/7UfERJlRwfBEeq+JifcWECqJW04BhdCsYMMb9dhV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}