SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08c8bdee22d6460395219f9e5cfb0a098de27903197397d423047062c4c25473' 
  AND token = 'cdfXl4nRJL7VIVt6w/AVnNdD1fRAa052RRVizIefrO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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