SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64a7e59c80336ec0797eb4c47fe7396e93e381fedbffc2a10ab192292f41cbb3' 
  AND token = 'xkH00nQaF3uwBG8nLZs6uVY6l9rwCqjULlszhZlL59E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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