SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5975e52a02889c3f9b24c3700ef8a304788c2c9985b89a23a0328dd4ec29a860' 
  AND token = 'Ynr2Srjv7ObPeSLsPIkUQJg9pEPazcu/yAVV5Tulpes=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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