SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '097ba5974fbc576abdf832d3e76dfa78a9c4b7c6468c21208037c5bee1f726de' 
  AND token = 'z0XzopzQ8/4Mz+5QPj5w9ItUith+RtbqGVfsMlnORTk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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