SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b5f37283538ad6908c453867c59e0347c67713d381d6f2e338d5261acc1ee9f' 
  AND token = 'J9QhvMZYKQpTIAf2AkiIT73aKyaP9VbMaDXUFzUfHCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}