SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc75898345964116f4c52f7bb6334638548cd25f844eeaded22c4f42193df213' 
  AND token = '03vqtfzFjhkBoC2RwCLc7CfIM/Mes+Es84yUuNF8nag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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