SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '465c9066aff5dd489c8a9a60b74cf6999850f8b27c5f15a32ed45b12a6b4f209' 
  AND token = 'uSl93arMNm5v1nlLi/0dg3te05YzAaWMqSM/hVXKLB0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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