SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8e0015fcaa89186ccb181e8a32fc3fcff8e49edfbec4cb49c14eff734f46c29' 
  AND token = 'pMUlRQnUGiefOUuBMisLzR59FwyTxe2Q2nU//hf12iQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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