SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03ec19cdaef35e17cac2ecb5f7cdd717438bf10704d8021c2b6da3eac5926278' 
  AND token = 'cjhXxnmjQ3XJGHeEWWXxQh/gmsBbbuEZIUdGRIfGy1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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