SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8cb5eb0ee78851a6075c5e1003ff4c1cc5dda918ab931fc018891bc552e61c8' 
  AND token = 'A1JXiOe+s7bmsdLmHyV2NjzaARhig3AsSEDUTJDwyj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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