SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12e70acaa63525a8ae74e519a4f95855e7157f36ea31a9bbe3cdddb80649d27d' 
  AND token = 'ttBXlGafKDDjBKn+bfIRVKOKVkJ+U4cMjnepMSw5u8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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