SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c9c3b4d3f891381551bebfbd7d9c84587182926a008863e991b0cc1d12fedb5' 
  AND token = 'VTPkfXGwS7VqZrLVostvYB5xLh2CsDXw8Na7dftlHls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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