SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '394f4354393900c0789d8de295fb1a7e5b2065ada5c6315e5b13a2268c01f9fa' 
  AND token = '1QWtUVz8vEoxZp1P+iKvBdqmE3+Y4G3ZAngY74k3E78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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