SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6009439572d6c024a5234ed0fdd56e4dafbfc1743975c851a313888acde8e2f' 
  AND token = 'r4hseTioM4J+/oIH7SXMbefvO9Fu2pZIrRr+wVxGyYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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