SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bfef20547c24b347bb643cd83d7a062b3931eabb2a51f613a5719141b98ba85' 
  AND token = '3/EPUtDluoxlKNmI1aRDXbOUvDXTg/UW/zEvGVuHqhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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