SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69f643d6baa5bcdb9567d24523623ee781d9feb30d2904c34d524395f27b550b' 
  AND token = 'NCudtMGk5A4D008ISWkrMLt8uH6xSdI5IVRjVrTmMNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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