SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2444d332b79c1d75280eed1153a06198cc21f8aa2a52f5c52b4e28f2d1ba0f08' 
  AND token = 'UGihVEzAa47ZAXlsSyVZ3PoM/GhBJ8kpHJf7dXQ3tgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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