SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59ab4061405752e4934f24a658b5456b759fd4434901c08c5e6904b8165874ba' 
  AND token = 'poLYmdgj/w2FqShvYnSAo98vaDCtgGfN0cUy3GxJ1LE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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