SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23b6bfdd7a052fa9f1f144b59b32958cc8add416c34f04e49761c71793e8a58e' 
  AND token = 'mXUfohGE8Uhca0caZFs9c89O2WjANQfpclvOBgqVJsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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