SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '918d8ae828c30bdbc57930c375ebe182a0d035834e41e9b0650505704a778481' 
  AND token = 'QShSHwElCR1rFVHu5O1LpGWVroio6SlapRHIGj5GyXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00077

JSON explain

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