SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e12e3655ea4c923f5799cae764b14814ccbe55438482f69d6f93abaa803a6be7' 
  AND token = '7Rg4bXqeP6o8AZujUVzzKVDc77+akTE8iWsacY3YkaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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