SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8523ea93534ab2f9a53932e609674ed4ccb6526b49cff386a3c745cd46faa91d' 
  AND token = 'SOoaGTzkRWSqFXfXvFWj8IniP56PoczIA6Hmy1JbCCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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