SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '214a01976c1648acf566af813194d0895341cc58b90fd0a35e8ee5c9a491db0a' 
  AND token = 'kC6lBzYzGs9GduB4HR+cyRqSlJ3wKhp8hfy+NG5kUJI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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