SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be425c82d6f8ffabb10cdd030b1c0eec0200885d524168c2664fb8b0a204e604' 
  AND token = '9hxXxvJkWIIw0XDcTwssGntSxmqAP8MNDcj2DMrkZMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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