SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b407dd3e25ed6363ac289e7b735d831505ab8d392d398bc86f5fbbe52aea5333' 
  AND token = 'cnJkTjC44qRINpV9KDcYwSscBs/BcGdQUTnn0poVpDU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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