SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5418aca3674388eaf7a6458bc91d89b457f06dfd94397a458573d390b6e69a75' 
  AND token = 'Ls5jyr0S7umE6vYOmPEMax7JkscqwS/Unr/jCP5HBsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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