SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5ed030c5f4854232af903f672d6962cef0a6977931f671c379a946c325291f8' 
  AND token = '1GLIp/29Ym7Qu4TgP25uNZpvImyxi8Wkf4uoMY8F9gI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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