SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef53443cc93821ab2f6a330e4aaeefa4d67fd0918ea090a67e4bfae5bf4ca180' 
  AND token = 'ykJR4rfeAQKi9YSLuYMWRXLxJh+jkKLqNxJAUb9Tkh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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