SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9981ec97170a0f3fffc6a4fd0c73e7e85f1b144dbd44d86d9fa74ed09b96c481' 
  AND token = 'mYufB4niodY58udUFSWd6Ckf7/+PJ1LeRotBVUyZIrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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