SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6eb2bdd7815d58ffe689ac972f3c2c1d6a53797396a779850425a85ba328b7f' 
  AND token = 'XZ63aYlHoZgACt9tpcpFgC+XroZrty56tqSe7N9FByU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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