SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f1c3694bdcad5aba03d5f352c06d6a9fa11e6850cc50580222a019299e92b64' 
  AND token = 'T4CTgckkcJO/KYWXVsWzFpfbgFesgZWBuCkQlbDkBNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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