SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96e3bf2ae6e4ad7a23bcafd4685577021c527c462d7d292eded4749f9ace034f' 
  AND token = '2ynMJ1lpjeSzThWNe7zrXoWX5VPxoIOcwuzkVk1Xfk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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