SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '718835a7d0eaf3fd4f65da57841d13b7114384f490664c8ecb9e3af852f39435' 
  AND token = 'zz4sL7xXLSxyIg1wyZcY58FPyqoM8ddnzOULK7Wyfk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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