SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcc94d88bbec9773f00e4793a3ea7e122fcc588cf1de40b6df77d0481de3996c' 
  AND token = 'E5rEGTcWDIqZKgbTj4qQZcdv4Lu79BuF8GSmfiiZtRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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